Provided by: drbd-utils_8.9.6-1_i386 bug

NAME

       drbdsetup - Setup tool for DRBD

SYNOPSIS

       drbdsetup new-resource resource [--cpu-mask {val}]
                 [--on-no-data-accessible {io-error | suspend-io}]

       drbdsetup new-minor resource minor volume

       drbdsetup del-resource resource

       drbdsetup del-minor minor

       drbdsetup attach minor lower_dev meta_data_dev meta_data_index
                 [--size {val}] [--max-bio-bvecs {val}]
                 [--on-io-error {pass_on | call-local-io-error | detach}]
                 [--fencing {dont-care | resource-only | resource-and-stonith}]
                 [--disk-barrier] [--disk-flushes] [--disk-drain]
                 [--md-flushes] [--resync-rate {val}] [--resync-after {val}]
                 [--al-extents {val}] [--al-updates]
                 [--discard-zeroes-if-aligned] [--c-plan-ahead {val}]
                 [--c-delay-target {val}] [--c-fill-target {val}]
                 [--c-max-rate {val}] [--c-min-rate {val}]
                 [--disk-timeout {val}]
                 [--read-balancing {prefer-local | prefer-remote | round-robin | least-pending | when-congested-remote | 32K-striping | 64K-striping | 128K-striping | 256K-striping | 512K-striping | 1M-striping}]
                 [--rs-discard-granularity {val}]

       drbdsetup connect resource local_addr remote_addr [--tentative]
                 [--discard-my-data] [--protocol {A | B | C}]
                 [--timeout {val}] [--max-epoch-size {val}]
                 [--max-buffers {val}] [--unplug-watermark {val}]
                 [--connect-int {val}] [--ping-int {val}]
                 [--sndbuf-size {val}] [--rcvbuf-size {val}]
                 [--ko-count {val}] [--allow-two-primaries]
                 [--cram-hmac-alg {val}] [--shared-secret {val}]
                 [--after-sb-0pri {disconnect | discard-younger-primary | discard-older-primary | discard-zero-changes | discard-least-changes | discard-local | discard-remote}]
                 [--after-sb-1pri {disconnect | consensus | discard-secondary | call-pri-lost-after-sb | violently-as0p}]
                 [--after-sb-2pri {disconnect | call-pri-lost-after-sb | violently-as0p}]
                 [--always-asbp]
                 [--rr-conflict {disconnect | call-pri-lost | violently}]
                 [--ping-timeout {val}] [--data-integrity-alg {val}]
                 [--tcp-cork]
                 [--on-congestion {block | pull-ahead | disconnect}]
                 [--congestion-fill {val}] [--congestion-extents {val}]
                 [--csums-alg {val}] [--csums-after-crash-only]
                 [--verify-alg {val}] [--use-rle]
                 [--socket-check-timeout {val}]

       drbdsetup disk-options minor
                 [--on-io-error {pass_on | call-local-io-error | detach}]
                 [--fencing {dont-care | resource-only | resource-and-stonith}]
                 [--disk-barrier] [--disk-flushes] [--disk-drain]
                 [--md-flushes] [--resync-rate {val}] [--resync-after {val}]
                 [--al-extents {val}] [--al-updates]
                 [--discard-zeroes-if-aligned] [--c-plan-ahead {val}]
                 [--c-delay-target {val}] [--c-fill-target {val}]
                 [--c-max-rate {val}] [--c-min-rate {val}]
                 [--disk-timeout {val}]
                 [--read-balancing {prefer-local | prefer-remote | round-robin | least-pending | when-congested-remote | 32K-striping | 64K-striping | 128K-striping | 256K-striping | 512K-striping | 1M-striping}]
                 [--rs-discard-granularity {val}]

       drbdsetup net-options local_addr remote_addr [--protocol {A | B | C}]
                 [--timeout {val}] [--max-epoch-size {val}]
                 [--max-buffers {val}] [--unplug-watermark {val}]
                 [--connect-int {val}] [--ping-int {val}]
                 [--sndbuf-size {val}] [--rcvbuf-size {val}]
                 [--ko-count {val}] [--allow-two-primaries]
                 [--cram-hmac-alg {val}] [--shared-secret {val}]
                 [--after-sb-0pri {disconnect | discard-younger-primary | discard-older-primary | discard-zero-changes | discard-least-changes | discard-local | discard-remote}]
                 [--after-sb-1pri {disconnect | consensus | discard-secondary | call-pri-lost-after-sb | violently-as0p}]
                 [--after-sb-2pri {disconnect | call-pri-lost-after-sb | violently-as0p}]
                 [--always-asbp]
                 [--rr-conflict {disconnect | call-pri-lost | violently}]
                 [--ping-timeout {val}] [--data-integrity-alg {val}]
                 [--tcp-cork]
                 [--on-congestion {block | pull-ahead | disconnect}]
                 [--congestion-fill {val}] [--congestion-extents {val}]
                 [--csums-alg {val}] [--csums-after-crash-only]
                 [--verify-alg {val}] [--use-rle]
                 [--socket-check-timeout {val}]

       drbdsetup resource-options resource [--cpu-mask {val}]
                 [--on-no-data-accessible {io-error | suspend-io}]

       drbdsetup disconnect local_addr remote_addr [--force]

       drbdsetup detach minor [--force]

       drbdsetup primary minor [--force]

       drbdsetup secondary minor

       drbdsetup down resource

       drbdsetup verify minor [--start {val}] [--stop {val}]

       drbdsetup invalidate minor

       drbdsetup invalidate-remote minor

       drbdsetup wait-connect minor [--wfc-timeout {val}]
                 [--degr-wfc-timeout {val}] [--outdated-wfc-timeout {val}]
                 [--wait-after-sb {val}]

       drbdsetup wait-sync minor [--wfc-timeout {val}]
                 [--degr-wfc-timeout {val}] [--outdated-wfc-timeout {val}]
                 [--wait-after-sb {val}]

       drbdsetup role minor

       drbdsetup cstate minor

       drbdsetup dstate minor

       drbdsetup resize minor [--size {val}] [--assume-peer-has-space]
                 [--assume-clean] [--al-stripes {val}]
                 [--al-stripe-size-kB {val}]

       drbdsetup check-resize minor

       drbdsetup pause-sync minor

       drbdsetup resume-sync minor

       drbdsetup outdate minor

       drbdsetup show-gi minor

       drbdsetup get-gi minor

       drbdsetup show {resource | minor | all}

       drbdsetup suspend-io minor

       drbdsetup resume-io minor

       drbdsetup status {resource | all} [--color {val}]

       drbdsetup events2 {resource | all}

       drbdsetup events {resource | minor | all}

       drbdsetup new-current-uuid minor [--clear-bitmap]

DESCRIPTION

       drbdsetup is used to associate DRBD devices with their backing block
       devices, to set up DRBD device pairs to mirror their backing block
       devices, and to inspect the configuration of running DRBD devices.

NOTE

       drbdsetup is a low level tool of the DRBD program suite. It is used by
       the data disk and drbd scripts to communicate with the device driver.

COMMANDS

       Each drbdsetup sub-command might require arguments and bring its own
       set of options. All values have default units which might be overruled
       by K, M or G. These units are defined in the usual way (e.g. K = 2^10 =
       1024).

   Common options
       All drbdsetup sub-commands accept these two options

       --create-device
           In case the specified DRBD device (minor number) does not exist
           yet, create it implicitly.

   new-resource
       Resources are the primary objects of any DRBD configuration. A resource
       must be created with the new-resource command before any volumes or
       minor devices can be created. Connections are referenced by name.

   new-minor
       A minor is used as a synonym for replicated block device. It is
       represented in the /dev/ directory by a block device. It is the
       application's interface to the DRBD-replicated block devices. These
       block devices get addressed by their minor numbers on the drbdsetup
       commandline.

       A pair of replicated block devices may have different minor numbers on
       the two machines. They are associated by a common volume-number. Volume
       numbers are local to each connection. Minor numbers are global on one
       node.

   del-resource
       Destroys a resource object. This is only possible if the resource has
       no volumes.

   del-minor
       Minors can only be destroyed if its disk is detached.

   attach, disk-options
       Attach associates device with lower_device to store its data blocks on.
       The -d (or --disk-size) should only be used if you wish not to use as
       much as possible from the backing block devices. If you do not use -d,
       the device is only ready for use as soon as it was connected to its
       peer once. (See the net command.)

       With the disk-options command it is possible to change the options of a
       minor while it is attached.

       --disk-size size
           You can override DRBD's size determination method with this option.
           If you need to use the device before it was ever connected to its
           peer, use this option to pass the size of the DRBD device to the
           driver. Default unit is sectors (1s = 512 bytes).

           If you use the size parameter in drbd.conf, we strongly recommend
           to add an explicit unit postfix. drbdadm and drbdsetup used to have
           mismatching default units.

       --on-io-error err_handler
           If the driver of the lower_device reports an error to DRBD, DRBD
           will mark the disk as inconsistent, call a helper program, or
           detach the device from its backing storage and perform all further
           IO by requesting it from the peer. The valid err_handlers are:
           pass_on, call-local-io-error and detach.

       --fencing fencing_policy
           Under fencing we understand preventive measures to avoid situations
           where both nodes are primary and disconnected (AKA split brain).

           Valid fencing policies are:

           dont-care
               This is the default policy. No fencing actions are done.

           resource-only
               If a node becomes a disconnected primary, it tries to outdate
               the peer's disk. This is done by calling the fence-peer
               handler. The handler is supposed to reach the other node over
               alternative communication paths and call 'drbdadm outdate res'
               there.

           resource-and-stonith
               If a node becomes a disconnected primary, it freezes all its IO
               operations and calls its fence-peer handler. The fence-peer
               handler is supposed to reach the peer over alternative
               communication paths and call 'drbdadm outdate res' there. In
               case it cannot reach the peer, it should stonith the peer. IO
               is resumed as soon as the situation is resolved. In case your
               handler fails, you can resume IO with the resume-io command.

       --disk-barrier,
       --disk-flushes,
       --disk-drain
           DRBD has four implementations to express write-after-write
           dependencies to its backing storage device. DRBD will use the first
           method that is supported by the backing storage device and that is
           not disabled. By default the flush method is used.

           Since drbd-8.4.2 disk-barrier is disabled by default because since
           linux-2.6.36 (or 2.6.32 RHEL6) there is no reliable way to
           determine if queuing of IO-barriers works.  Dangerous only enable
           if you are told so by one that knows for sure.

           When selecting the method you should not only base your decision on
           the measurable performance. In case your backing storage device has
           a volatile write cache (plain disks, RAID of plain disks) you
           should use one of the first two. In case your backing storage
           device has battery-backed write cache you may go with option 3.
           Option 4 (disable everything, use "none") is dangerous on most IO
           stacks, may result in write-reordering, and if so, can
           theoretically be the reason for data corruption, or disturb the
           DRBD protocol, causing spurious disconnect/reconnect cycles.  Do
           not use no-disk-drain.

           Unfortunately device mapper (LVM) might not support barriers.

           The letter after "wo:" in /proc/drbd indicates with method is
           currently in use for a device: b, f, d, n. The implementations:

           barrier
               The first requires that the driver of the backing storage
               device support barriers (called 'tagged command queuing' in
               SCSI and 'native command queuing' in SATA speak). The use of
               this method can be enabled by setting the disk-barrier options
               to yes.

           flush
               The second requires that the backing device support disk
               flushes (called 'force unit access' in the drive vendors
               speak). The use of this method can be disabled setting
               disk-flushes to no.

           drain
               The third method is simply to let write requests drain before
               write requests of a new reordering domain are issued. That was
               the only implementation before 8.0.9.

           none
               The fourth method is to not express write-after-write
               dependencies to the backing store at all, by also specifying
               --no-disk-drain. This is dangerous on most IO stacks, may
               result in write-reordering, and if so, can theoretically be the
               reason for data corruption, or disturb the DRBD protocol,
               causing spurious disconnect/reconnect cycles.  Do not use
               --no-disk-drain.

       --md-flushes
           Disables the use of disk flushes and barrier BIOs when accessing
           the meta data device. See the notes on --disk-flushes.

       --max-bio-bvecs
           In some special circumstances the device mapper stack manages to
           pass BIOs to DRBD that violate the constraints that are set forth
           by DRBD's merge_bvec() function and which have more than one bvec.
           A known example is: phys-disk -> DRBD -> LVM -> Xen -> missaligned
           partition (63) -> DomU FS. Then you might see "bio would need to,
           but cannot, be split:" in the Dom0's kernel log.

           The best workaround is to proper align the partition within the VM
           (E.g. start it at sector 1024). That costs 480 KiB of storage.
           Unfortunately the default of most Linux partitioning tools is to
           start the first partition at an odd number (63). Therefore most
           distributions install helpers for virtual linux machines will end
           up with missaligned partitions. The second best workaround is to
           limit DRBD's max bvecs per BIO (i.e., the max-bio-bvecs option) to
           1, but that might cost performance.

           The default value of max-bio-bvecs is 0, which means that there is
           no user imposed limitation.

       --resync-rate rate
           To ensure smooth operation of the application on top of DRBD, it is
           possible to limit the bandwidth that may be used by background
           synchronization. The default is 250 KiB/sec, the default unit is
           KiB/sec.

       --resync-after minor
           Start resync on this device only if the device with minor is
           already in connected state. Otherwise this device waits in
           SyncPause state.

       --al-extents extents
           DRBD automatically performs hot area detection. With this parameter
           you control how big the hot area (=active set) can get. Each extent
           marks 4M of the backing storage. In case a primary node leaves the
           cluster unexpectedly, the areas covered by the active set must be
           resynced upon rejoining of the failed node. The data structure is
           stored in the meta-data area, therefore each change of the active
           set is a write operation to the meta-data device. A higher number
           of extents gives longer resync times but less updates to the
           meta-data. The default number of extents is 1237. (Minimum: 7,
           Maximum: 65534)

           See also drbd.conf(5) and drbdmeta(8) for additional limitations
           and necessary preparation.

       --al-updates {yes | no}
           DRBD's activity log transaction writing makes it possible, that
           after the crash of a primary node a partial (bit-map based) resync
           is sufficient to bring the node back to up-to-date. Setting
           al-updates to no might increase normal operation performance but
           causes DRBD to do a full resync when a crashed primary gets
           reconnected. The default value is yes.

       --c-plan-ahead plan_time,
       --c-fill-target fill_target,
       --c-delay-target delay_target,
       --c-max-rate max_rate
           The dynamic resync speed controller gets enabled with setting
           plan_time to a positive value. It aims to fill the buffers along
           the data path with either a constant amount of data fill_target, or
           aims to have a constant delay time of delay_target along the path.
           The controller has an upper bound of max_rate.

           By plan_time the agility of the controller is configured. Higher
           values yield for slower/lower responses of the controller to
           deviation from the target value. It should be at least 5 times RTT.
           For regular data paths a fill_target in the area of 4k to 100k is
           appropriate. For a setup that contains drbd-proxy it is advisable
           to use delay_target instead. Only when fill_target is set to 0 the
           controller will use delay_target. 5 times RTT is a reasonable
           starting value.  Max_rate should be set to the bandwidth available
           between the DRBD-hosts and the machines hosting DRBD-proxy, or to
           the available disk-bandwidth.

           The default value of plan_time is 0, the default unit is 0.1
           seconds.  Fill_target has 0 and sectors as default unit.
           Delay_target has 1 (100ms) and 0.1 as default unit.  Max_rate has
           10240 (100MiB/s) and KiB/s as default unit.

       --c-min-rate min_rate
           We track the disk IO rate caused by the resync, so we can detect
           non-resync IO on the lower level device. If the lower level device
           seems to be busy, and the current resync rate is above min_rate, we
           throttle the resync.

           The default value of min_rate is 4M, the default unit is k. If you
           want to not throttle at all, set it to zero, if you want to
           throttle always, set it to one.

       -t, --disk-timeout disk_timeout
           If the lower-level device on which a DRBD device stores its data
           does not finish an I/O request within the defined disk-timeout,
           DRBD treats this as a failure. The lower-level device is detached,
           and the device's disk state advances to Diskless. If DRBD is
           connected to one or more peers, the failed request is passed on to
           one of them.

           This option is dangerous and may lead to kernel panic!

           "Aborting" requests, or force-detaching the disk, is intended for
           completely blocked/hung local backing devices which do no longer
           complete requests at all, not even do error completions. In this
           situation, usually a hard-reset and failover is the only way out.

           By "aborting", basically faking a local error-completion, we allow
           for a more graceful swichover by cleanly migrating services. Still
           the affected node has to be rebooted "soon".

           By completing these requests, we allow the upper layers to re-use
           the associated data pages.

           If later the local backing device "recovers", and now DMAs some
           data from disk into the original request pages, in the best case it
           will just put random data into unused pages; but typically it will
           corrupt meanwhile completely unrelated data, causing all sorts of
           damage.

           Which means delayed successful completion, especially for READ
           requests, is a reason to panic(). We assume that a delayed *error*
           completion is OK, though we still will complain noisily about it.

           The default value of disk-timeout is 0, which stands for an
           infinite timeout. Timeouts are specified in units of 0.1 seconds.
           This option is available since DRBD 8.3.12.

       --discard-zeroes-if-aligned {yes | no}
           Setting discard-zeroes-if-aligned to no will cause DRBD to always
           fall-back to zero-out on the receiving side, and to not even
           announce discard capabilities on the Primary, if the respective
           backend announces discard_zeroes_data=false.

           Setting discards-zeroes-if-aligned to yes will allow DRBD to use
           discards, and to announce discard_zeroes=true, even on backends
           that announce discard_zeroes_data=false.

           We used to ignore the discard_zeroes_data setting completely. To
           not break established and expected behaviour, the default value is
           yes.

           This option is available since 8.4.7. See also drbd.conf(5).

       --read-balancing method
           The supported methods for load balancing of read requests are
           prefer-local, prefer-remote, round-robin, least-pending and
           when-congested-remote, 32K-striping, 64K-striping, 128K-striping,
           256K-striping, 512K-striping and 1M-striping.

           The default value of is prefer-local. This option is available
           since 8.4.1.

       --rs-discard-granularity bytes
           When rs-discard-granularity is set to a non zero, positive value
           then DRBD tries to do a resync operation in requests of this size.
           In case such a block contains only zero bytes on the sync source
           node, the sync target node will issue a discard/trim/unmap command
           for the area.

           The value is constrained by the discard granularity of the backing
           block device. In case rs-discard-granularity is not a multiplier of
           the discard granularity of the backing block device DRBD rounds it
           up. The feature only gets active if the backing block device reads
           back zeroes after a discard command.

           The default value of is 0. This option is available since 8.4.7.

   connect, net-options
       Connect sets up the device to listen on af:local_addr:port for incoming
       connections and to try to connect to af:remote_addr:port. If port is
       omitted, 7788 is used as default. If af is omitted ipv4 gets used.
       Other supported address families are ipv6, ssocks for Dolphin
       Interconnect Solutions' "super sockets" and sdp for Sockets Direct
       Protocol (Infiniband).

       The net-options command allows you to change options while the
       connection is established.

       --protocol protocol
           On the TCP/IP link the specified protocol is used. Valid protocol
           specifiers are A, B, and C.

           Protocol A: write IO is reported as completed, if it has reached
           local disk and local TCP send buffer.

           Protocol B: write IO is reported as completed, if it has reached
           local disk and remote buffer cache.

           Protocol C: write IO is reported as completed, if it has reached
           both local and remote disk.

       --connect-int time
           In case it is not possible to connect to the remote DRBD device
           immediately, DRBD keeps on trying to connect. With this option you
           can set the time between two retries. The default value is 10. The
           unit is seconds.

       --ping-int time
           If the TCP/IP connection linking a DRBD device pair is idle for
           more than time seconds, DRBD will generate a keep-alive packet to
           check if its partner is still alive. The default value is 10. The
           unit is seconds.

       --timeout val
           If the partner node fails to send an expected response packet
           within val tenths of a second, the partner node is considered dead
           and therefore the TCP/IP connection is abandoned. The default value
           is 60 (= 6 seconds).

       --sndbuf-size size
           The socket send buffer is used to store packets sent to the
           secondary node, which are not yet acknowledged (from a network
           point of view) by the secondary node. When using protocol A, it
           might be necessary to increase the size of this data structure in
           order to increase asynchronicity between primary and secondary
           nodes. But keep in mind that more asynchronicity is synonymous with
           more data loss in the case of a primary node failure. Since 8.0.13
           resp. 8.2.7 setting the size value to 0 means that the kernel
           should autotune this. The default size is 0, i.e. autotune.

       --rcvbuf-size size
           Packets received from the network are stored in the socket receive
           buffer first. From there they are consumed by DRBD. Before 8.3.2
           the receive buffer's size was always set to the size of the socket
           send buffer. Since 8.3.2 they can be tuned independently. A value
           of 0 means that the kernel should autotune this. The default size
           is 0, i.e. autotune.

       --ko-count count
           In case the secondary node fails to complete a single write request
           for count times the timeout, it is expelled from the cluster, i.e.
           the primary node goes into StandAlone mode. To disable this
           feature, you should explicitly set it to 0; defaults may change
           between versions.

       --max-epoch-size val
           With this option the maximal number of write requests between two
           barriers is limited. Typically set to the same as --max-buffers, or
           the allowed maximum. Values smaller than 10 can lead to degraded
           performance. The default value is 2048.

       --max-buffers val
           With this option the maximal number of buffer pages allocated by
           DRBD's receiver thread is limited. Typically set to the same as
           --max-epoch-size. Small values could lead to degraded performance.
           The default value is 2048, the minimum 32. Increase this if you
           cannot saturate the IO backend of the receiving side during linear
           write or during resync while otherwise idle.

           See also drbd.conf(5)

       --unplug-watermark val
           This setting has no effect with recent kernels that use explicit
           on-stack plugging (upstream Linux kernel 2.6.39, distributions may
           have backported).

           When the number of pending write requests on the standby
           (secondary) node exceeds the unplug-watermark, we trigger the
           request processing of our backing storage device. Some storage
           controllers deliver better performance with small values, others
           deliver best performance when the value is set to the same value as
           max-buffers, yet others don't feel much effect at all. Minimum 16,
           default 128, maximum 131072.

       --allow-two-primaries
           With this option set you may assign primary role to both nodes. You
           only should use this option if you use a shared storage file system
           on top of DRBD. At the time of writing the only ones are: OCFS2 and
           GFS. If you use this option with any other file system, you are
           going to crash your nodes and to corrupt your data!

       --cram-hmac-alg alg
           You need to specify the HMAC algorithm to enable peer
           authentication at all. You are strongly encouraged to use peer
           authentication. The HMAC algorithm will be used for the challenge
           response authentication of the peer. You may specify any digest
           algorithm that is named in /proc/crypto.

       --shared-secret secret
           The shared secret used in peer authentication. May be up to 64
           characters.

       --after-sb-0pri asb-0p-policy
           possible policies are:

           disconnect
               No automatic resynchronization, simply disconnect.

           discard-younger-primary
               Auto sync from the node that was primary before the split-brain
               situation occurred.

           discard-older-primary
               Auto sync from the node that became primary as second during
               the split-brain situation.

           discard-zero-changes
               In case one node did not write anything since the split brain
               became evident, sync from the node that wrote something to the
               node that did not write anything. In case none wrote anything
               this policy uses a random decision to perform a "resync" of 0
               blocks. In case both have written something this policy
               disconnects the nodes.

           discard-least-changes
               Auto sync from the node that touched more blocks during the
               split brain situation.

           discard-node-NODENAME
               Auto sync to the named node.

       --after-sb-1pri asb-1p-policy
           possible policies are:

           disconnect
               No automatic resynchronization, simply disconnect.

           consensus
               Discard the version of the secondary if the outcome of the
               after-sb-0pri algorithm would also destroy the current
               secondary's data. Otherwise disconnect.

           discard-secondary
               Discard the secondary's version.

           call-pri-lost-after-sb
               Always honor the outcome of the after-sb-0pri algorithm. In
               case it decides the current secondary has the correct data,
               call the pri-lost-after-sb on the current primary.

           violently-as0p
               Always honor the outcome of the after-sb-0pri algorithm. In
               case it decides the current secondary has the correct data,
               accept a possible instantaneous change of the primary's data.

       --after-sb-2pri asb-2p-policy
           possible policies are:

           disconnect
               No automatic resynchronization, simply disconnect.

           call-pri-lost-after-sb
               Always honor the outcome of the after-sb-0pri algorithm. In
               case it decides the current secondary has the right data, call
               the pri-lost-after-sb on the current primary.

           violently-as0p
               Always honor the outcome of the after-sb-0pri algorithm. In
               case it decides the current secondary has the right data,
               accept a possible instantaneous change of the primary's data.

       --always-asbp
           Normally the automatic after-split-brain policies are only used if
           current states of the UUIDs do not indicate the presence of a third
           node.

           With this option you request that the automatic after-split-brain
           policies are used as long as the data sets of the nodes are somehow
           related. This might cause a full sync, if the UUIDs indicate the
           presence of a third node. (Or double faults have led to strange
           UUID sets.)

       --rr-conflict role-resync-conflict-policy
           This option sets DRBD's behavior when DRBD deduces from its meta
           data that a resynchronization is needed, and the SyncTarget node is
           already primary. The possible settings are: disconnect,
           call-pri-lost and violently. While disconnect speaks for itself,
           with the call-pri-lost setting the pri-lost handler is called which
           is expected to either change the role of the node to secondary, or
           remove the node from the cluster. The default is disconnect.

           With the violently setting you allow DRBD to force a primary node
           into SyncTarget state. This means that the data exposed by DRBD
           changes to the SyncSource's version of the data instantaneously.
           USE THIS OPTION ONLY IF YOU KNOW WHAT YOU ARE DOING.

       --data-integrity-alg hash_alg
           DRBD can ensure the data integrity of the user's data on the
           network by comparing hash values. Normally this is ensured by the
           16 bit checksums in the headers of TCP/IP packets. This option can
           be set to any of the kernel's data digest algorithms. In a typical
           kernel configuration you should have at least one of md5, sha1, and
           crc32c available. By default this is not enabled.

           See also the notes on data integrity on the drbd.conf manpage.

       --no-tcp-cork
           DRBD usually uses the TCP socket option TCP_CORK to hint to the
           network stack when it can expect more data, and when it should
           flush out what it has in its send queue. There is at least one
           network stack that performs worse when one uses this hinting
           method. Therefore we introduced this option, which disable the
           setting and clearing of the TCP_CORK socket option by DRBD.

       --ping-timeout ping_timeout
           The time the peer has to answer to a keep-alive packet. In case the
           peer's reply is not received within this time period, it is
           considered dead. The default unit is tenths of a second, the
           default value is 5 (for half a second).

       --discard-my-data
           Use this option to manually recover from a split-brain situation.
           In case you do not have any automatic after-split-brain policies
           selected, the nodes refuse to connect. By passing this option you
           make this node a sync target immediately after successful connect.

       --tentative
           Causes DRBD to abort the connection process after the resync
           handshake, i.e. no resync gets performed. You can find out which
           resync DRBD would perform by looking at the kernel's log file.

       --on-congestion congestion_policy,
       --congestion-fill fill_threshold,
       --congestion-extents active_extents_threshold
           By default DRBD blocks when the available TCP send queue becomes
           full. That means it will slow down the application that generates
           the write requests that cause DRBD to send more data down that TCP
           connection.

           When DRBD is deployed with DRBD-proxy it might be more desirable
           that DRBD goes into AHEAD/BEHIND mode shortly before the send queue
           becomes full. In AHEAD/BEHIND mode DRBD does no longer replicate
           data, but still keeps the connection open.

           The advantage of the AHEAD/BEHIND mode is that the application is
           not slowed down, even if DRBD-proxy's buffer is not sufficient to
           buffer all write requests. The downside is that the peer node falls
           behind, and that a resync will be necessary to bring it back into
           sync. During that resync the peer node will have an inconsistent
           disk.

           Available congestion_policys are block and pull-ahead. The default
           is block.  Fill_threshold might be in the range of 0 to 10GiBytes.
           The default is 0 which disables the check.
           Active_extents_threshold has the same limits as al-extents.

           The AHEAD/BEHIND mode and its settings are available since DRBD
           8.3.10.

       --verify-alg hash-alg
           During online verification (as initiated by the verify
           sub-command), rather than doing a bit-wise comparison, DRBD applies
           a hash function to the contents of every block being verified, and
           compares that hash with the peer. This option defines the hash
           algorithm being used for that purpose. It can be set to any of the
           kernel's data digest algorithms. In a typical kernel configuration
           you should have at least one of md5, sha1, and crc32c available. By
           default this is not enabled; you must set this option explicitly in
           order to be able to use on-line device verification.

           See also the notes on data integrity on the drbd.conf manpage.

       --csums-alg hash-alg
           A resync process sends all marked data blocks form the source to
           the destination node, as long as no csums-alg is given. When one is
           specified the resync process exchanges hash values of all marked
           blocks first, and sends only those data blocks over, that have
           different hash values.

           This setting is useful for DRBD setups with low bandwidth links.
           During the restart of a crashed primary node, all blocks covered by
           the activity log are marked for resync. But a large part of those
           will actually be still in sync, therefore using csums-alg will
           lower the required bandwidth in exchange for CPU cycles.

       --use-rle
           During resync-handshake, the dirty-bitmaps of the nodes are
           exchanged and merged (using bit-or), so the nodes will have the
           same understanding of which blocks are dirty. On large devices, the
           fine grained dirty-bitmap can become large as well, and the bitmap
           exchange can take quite some time on low-bandwidth links.

           Because the bitmap typically contains compact areas where all bits
           are unset (clean) or set (dirty), a simple run-length encoding
           scheme can considerably reduce the network traffic necessary for
           the bitmap exchange.

           For backward compatibility reasons, and because on fast links this
           possibly does not improve transfer time but consumes cpu cycles,
           this defaults to off.

           Introduced in 8.3.2.

       --socket-check-timeout
           In setups involving a DRBD-proxy and connections that experience a
           lot of buffer-bloat it might be necessary to set ping-timeout to an
           unusual high value. By default DRBD uses the same value to wait if
           a newly established TCP-connection is stable. Since the DRBD-proxy
           is usually located in the same data center such a long wait time
           may hinder DRBD's connect process.

           In such setups socket-check-timeout should be set to at least to
           the round trip time between DRBD and DRBD-proxy. I.e. in most cases
           to 1.

           The default unit is tenths of a second, the default value is 0
           (which causes DRBD to use the value of ping-timeout instead).
           Introduced in 8.4.5.

   resource-options
       Changes the options of the resource at runtime.

       --cpu-mask cpu-mask
           Sets the cpu-affinity-mask for DRBD's kernel threads of this
           device. The default value of cpu-mask is 0, which means that DRBD's
           kernel threads should be spread over all CPUs of the machine. This
           value must be given in hexadecimal notation. If it is too big it
           will be truncated.

       --on-no-data-accessible ond-policy
           This setting controls what happens to IO requests on a degraded,
           disk less node (I.e. no data store is reachable). The available
           policies are io-error and suspend-io.

           If ond-policy is set to suspend-io you can either resume IO by
           attaching/connecting the last lost data storage, or by the drbdadm
           resume-io res command. The latter will result in IO errors of
           course.

           The default is io-error. This setting is available since DRBD
           8.3.9.

   primary
       Sets the device into primary role. This means that applications (e.g. a
       file system) may open the device for read and write access. Data
       written to the device in primary role are mirrored to the device in
       secondary role.

       Normally it is not possible to set both devices of a connected DRBD
       device pair to primary role. By using the --allow-two-primaries option,
       you override this behavior and instruct DRBD to allow two primaries.

       --overwrite-data-of-peer
           Alias for --force.

       --force
           Becoming primary fails if the local replica is not up-to-date. I.e.
           when it is inconsistent, outdated of consistent. By using this
           option you can force it into primary role anyway. USE THIS OPTION
           ONLY IF YOU KNOW WHAT YOU ARE DOING.

   secondary
       Brings the device into secondary role. This operation fails as long as
       at least one application (or file system) has opened the device.

       It is possible that both devices of a connected DRBD device pair are
       secondary.

   verify
       This initiates on-line device verification. During on-line
       verification, the contents of every block on the local node are
       compared to those on the peer node. Device verification progress can be
       monitored via /proc/drbd. Any blocks whose content differs from that of
       the corresponding block on the peer node will be marked out-of-sync in
       DRBD's on-disk bitmap; they are not brought back in sync automatically.
       To do that, simply disconnect and reconnect the resource.

       If on-line verification is already in progress (and this node is
       "VerifyS"), this command silently "succeeds". In this case, any
       start-sector (see below) will be ignored, and any stop-sector (see
       below) will be honored. This can be used to stop a running verify, or
       to update/shorten/extend the coverage of the currently running verify.

       This command will fail if the device is not part of a connected device
       pair.

       See also the notes on data integrity on the drbd.conf manpage.

       --start start-sector
           Since version 8.3.2, on-line verification should resume from the
           last position after connection loss. It may also be started from an
           arbitrary position by setting this option. If you had reached some
           stop-sector before, and you do not specify an explicit
           start-sector, verify should resume from the previous stop-sector.

           Default unit is sectors. You may also specify a unit explicitly.
           The start-sector will be rounded down to a multiple of 8 sectors
           (4kB).

       -S, --stop stop-sector
           Since version 8.3.14, on-line verification can be stopped before it
           reaches end-of-device.

           Default unit is sectors. You may also specify a unit explicitly.
           The stop-sector may be updated by issuing an additional drbdsetup
           verify command on the same node while the verify is running. This
           can be used to stop a running verify, or to update/shorten/extend
           the coverage of the currently running verify.

   invalidate
       This forces the local device of a pair of connected DRBD devices into
       SyncTarget state, which means that all data blocks of the device are
       copied over from the peer.

       This command will fail if the device is not either part of a connected
       device pair, or disconnected Secondary.

   invalidate-remote
       This forces the local device of a pair of connected DRBD devices into
       SyncSource state, which means that all data blocks of the device are
       copied to the peer.

       On a disconnected Primary device, this will set all bits in the out of
       sync bitmap. As a side affect this suspends updates to the on disk
       activity log. Updates to the on disk activity log resume automatically
       when necessary.

   wait-connect
       Returns as soon as the device can communicate with its partner device.

       --wfc-timeout wfc_timeout,
       --degr-wfc-timeout degr_wfc_timeout,
       --outdated-wfc-timeout outdated_wfc_timeout,
       --wait-after-sb
           This command will fail if the device cannot communicate with its
           partner for timeout seconds. If the peer was working before this
           node was rebooted, the wfc_timeout is used. If the peer was already
           down before this node was rebooted, the degr_wfc_timeout is used.
           If the peer was successfully outdated before this node was rebooted
           the outdated_wfc_timeout is used. The default value for all those
           timeout values is 0 which means to wait forever. The unit is
           seconds. In case the connection status goes down to StandAlone
           because the peer appeared but the devices had a split brain
           situation, the default for the command is to terminate. You can
           change this behavior with the --wait-after-sb option.

   wait-sync
       Returns as soon as the device leaves any synchronization into connected
       state. The options are the same as with the wait-connect command.

   disconnect
       Removes the information set by the net command from the device. This
       means that the device goes into unconnected state and will no longer
       listen for incoming connections.

   detach
       Removes the information set by the disk command from the device. This
       means that the device is detached from its backing storage device.

       -f, --force
           A regular detach returns after the disk state finally reached
           diskless. As a consequence detaching from a frozen backing block
           device never terminates.

           On the other hand A forced detach returns immediately. It allows
           you to detach DRBD from a frozen backing block device. Please note
           that the disk will be marked as failed until all pending IO
           requests where finished by the backing block device.

   down
       Removes all configuration information from the device and forces it
       back to unconfigured state.

   role
       Shows the current roles of the device and its peer, as local/peer.

   state
       Deprecated alias for "role"

   cstate
       Shows the current connection state of the device.

   dstate
       Shows the current states of the backing storage devices, as local/peer.

   resize
       This causes DRBD to reexamine the size of the device's backing storage
       device. To actually do online growing you need to extend the backing
       storages on both devices and call the resize command on one of your
       nodes.

       The --size option can be used to online shrink the usable size of a
       drbd device. It's the users responsibility to make sure that a file
       system on the device is not truncated by that operation.

       The --assume-peer-has-space allows you to resize a device which is
       currently not connected to the peer. Use with care, since if you do not
       resize the peer's disk as well, further connect attempts of the two
       will fail.

       When the --assume-clean option is given DRBD will skip the resync of
       the new storage. Only do this if you know that the new storage was
       initialized to the same content by other means.

       The options --al-stripes and --al-stripe-size-kB may be used to change
       the layout of the activity log online. In case of internal meta data
       this may invovle shrinking the user visible size at the same time
       (unsing the --size) or increasing the avalable space on the backing
       devices.

   check-resize
       To enable DRBD to detect offline resizing of backing devices this
       command may be used to record the current size of backing devices. The
       size is stored in files in /var/lib/drbd/ named drbd-minor-??.lkbd

       This command is called by drbdadm resize res after drbdsetup device
       resize returned.

   pause-sync
       Temporarily suspend an ongoing resynchronization by setting the local
       pause flag. Resync only progresses if neither the local nor the remote
       pause flag is set. It might be desirable to postpone DRBD's
       resynchronization after eventual resynchronization of the backing
       storage's RAID setup.

   resume-sync
       Unset the local sync pause flag.

   outdate
       Mark the data on the local backing storage as outdated. An outdated
       device refuses to become primary. This is used in conjunction with
       fencing and by the peer's fence-peer handler.

   show-gi
       Displays the device's data generation identifiers verbosely.

   get-gi
       Displays the device's data generation identifiers.

   show
       Shows all available configuration information of a resource, or of all
       resources. Available options:

       --show-defaults
           Show all configuration parameters, even the ones with default
           values. Normally, parameters with default values are not shown.

   suspend-io
       This command is of no apparent use and just provided for the sake of
       completeness.

   resume-io
       If the fence-peer handler fails to stonith the peer node, and your
       fencing policy is set to resource-and-stonith, you can unfreeze IO
       operations with this command.

   status
       Show the status of a resource, or of all resources. The output consists
       of one paragraph for each configured resource. Each paragraph contains
       one line for each resource, followed by one line for each device, and
       one line for each connection. The device and connection lines are
       indented. The connection lines are followed by one line for each peer
       device; these lines are indented against the connection line.

       Long lines are wrapped around at terminal width, and indented to
       indicate how the lines belongs together. Available options:

       --verbose
           Include more information in the output even when it is likely
           redundant or irrelevant.

       --statistics
           Include data transfer statistics in the output.

       --color={always | auto | never}
           Colorize the output. With --color=auto, drbdsetup emits color codes
           only when standard output is connected to a terminal.

       For example, the non-verbose output for a resource with only one
       connection and only one volume could look like this:

           fs-backoffice role:Primary
             disk:UpToDate
             peer role:Secondary
               replication:Established peer-disk:UpToDate

       With the --verbose --statistics options, the same resource could be
       reported as:

           fs-data role:Primary suspended:no
               write-ordering:drain
             volume:0 minor:1 disk:UpToDate
                 size:10616472 read:134465 written:144800 al-writes:18 bm-writes:0
                 upper-pending:0 lower-pending:0 al-suspended:no blocked:no
             peer connection:Connected role:Secondary congested:no
               volume:0 replication:Established peer-disk:UpToDate resync-suspended:no
                   received:122596 sent:22204 out-of-sync:0 pending:0 unacked:0

   events2
       Show the current state of all configured DRBD objects, followed by all
       changes to the state.

       The output format is meant to be human as well as machine readable.
       Each line starts with the event number, which is followed by an
       asterisk if the event continues in the next line. The second word in
       each line indicates the kind of event: exists for an existing object;
       create, destroy, and change if an object is created, destroyed, or
       changed; or call or response if an event handler is called or it
       returns. The third word indicates the object the event applies to:
       resource, device, connection, peer-device, helper, or a dash (-) to
       indicate that the current state has been dumped completely.

       The remaining words identify the object and describe the state that he
       object is in. Available options:

       --now
           Terminate after reporting the current state. The default is to
           continuously listen and report state changes.

       --statistics
           Include statistics in the output.

   events
       Deprecated. If possible, change to the events2 subcommand instead.

       Displays every state change of DRBD and all calls to helper programs.
       This might be used to get notified of DRBD's state changes by piping
       the output to another program.

       --all-devices
           Display the events of all DRBD minors.

       --unfiltered
           This is a debugging aid that displays the content of all received
           netlink messages.

   new-current-uuid
       Generates a new current UUID and rotates all other UUID values. This
       has at least two use cases, namely to skip the initial sync, and to
       reduce network bandwidth when starting in a single node configuration
       and then later (re-)integrating a remote site.

       Available option:

       --clear-bitmap
           Clears the sync bitmap in addition to generating a new current
           UUID.

       This can be used to skip the initial sync, if you want to start from
       scratch. This use-case does only work on "Just Created" meta data.
       Necessary steps:

        1. On both nodes, initialize meta data and configure the device.

           drbdadm -- --force create-md res

        2. They need to do the initial handshake, so they know their sizes.

           drbdadm up res

        3. They are now Connected Secondary/Secondary
           Inconsistent/Inconsistent. Generate a new current-uuid and clear
           the dirty bitmap.

           drbdadm new-current-uuid --clear-bitmap res

        4. They are now Connected Secondary/Secondary UpToDate/UpToDate. Make
           one side primary and create a file system.

           drbdadm primary res

           mkfs -t fs-type $(drbdadm sh-dev res)

       One obvious side-effect is that the replica is full of old garbage
       (unless you made them identical using other means), so any
       online-verify is expected to find any number of out-of-sync blocks.

       You must not use this on pre-existing data!  Even though it may appear
       to work at first glance, once you switch to the other node, your data
       is toast, as it never got replicated. So do not leave out the mkfs (or
       equivalent).

       This can also be used to shorten the initial resync of a cluster where
       the second node is added after the first node is gone into production,
       by means of disk shipping. This use-case works on disconnected devices
       only, the device may be in primary or secondary role.

       The necessary steps on the current active server are:

        1. drbdsetup new-current-uuid --clear-bitmap minor

        2. Take the copy of the current active server. E.g. by pulling a disk
           out of the RAID1 controller, or by copying with dd. You need to
           copy the actual data, and the meta data.

        3. drbdsetup new-current-uuid minor

       Now add the disk to the new secondary node, and join it to the cluster.
       You will get a resync of that parts that were changed since the first
       call to drbdsetup in step 1.

EXAMPLES

       For examples, please have a look at the DRBD User's Guide[1].

VERSION

       This document was revised for version 8.3.2 of the DRBD distribution.

AUTHOR

       Written by Philipp Reisner <philipp.reisner@linbit.com> and Lars
       Ellenberg <lars.ellenberg@linbit.com>

REPORTING BUGS

       Report bugs to <drbd-user@lists.linbit.com>.

COPYRIGHT

       Copyright 2001-2008 LINBIT Information Technologies, Philipp Reisner,
       Lars Ellenberg. This is free software; see the source for copying
       conditions. There is NO warranty; not even for MERCHANTABILITY or
       FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO

       drbd.conf(5), drbd(8), drbddisk(8), drbdadm(8), DRBD User's Guide[1],
       DRBD web site[2]

NOTES

        1. DRBD User's Guide
           http://www.drbd.org/users-guide/

        2. DRBD web site
           http://www.drbd.org/