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NAME

     vinum -- Logical Volume Manager

SYNOPSIS

     device vinum

DESCRIPTION

     vinum is a logical volume manager inspired by, but not derived from, the
     Veritas Volume Manager.  It provides the following features:

     +o   It provides device-independent logical disks, called volumes.
         Volumes are not restricted to the size of any disk on the system.

     +o   The volumes consist of one or more plexes, each of which contain the
         entire address space of a volume.  This represents an implementation
         of RAID-1 (mirroring).  Multiple plexes can also be used for:

         +o   Increased read throughput.  vinum will read data from the least
             active disk, so if a volume has plexes on multiple disks, more
             data can be read in parallel.  vinum reads data from only one
             plex, but it writes data to all plexes.

         +o   Increased reliability.  By storing plexes on different disks,
             data will remain available even if one of the plexes becomes
             unavailable.  In comparison with a RAID-5 plex (see below), using
             multiple plexes requires more storage space, but gives better
             performance, particularly in the case of a drive failure.

         +o   Additional plexes can be used for on-line data reorganization.
             By attaching an additional plex and subsequently detaching one of
             the older plexes, data can be moved on-line without compromising
             access.

         +o   An additional plex can be used to obtain a consistent dump of a
             file system.  By attaching an additional plex and detaching at a
             specific time, the detached plex becomes an accurate snapshot of
             the file system at the time of detachment.

     +o   Each plex consists of one or more logical disk slices, called
         subdisks.  Subdisks are defined as a contiguous block of physical
         disk storage.  A plex may consist of any reasonable number of
         subdisks (in other words, the real limit is not the number, but other
         factors, such as memory and performance, associated with maintaining
         a large number of subdisks).

     +o   A number of mappings between subdisks and plexes are available:

         +o   Concatenated plexes consist of one or more subdisks, each of
             which is mapped to a contiguous part of the plex address space.

         +o   Striped plexes consist of two or more subdisks of equal size.
             The file address space is mapped in stripes, integral fractions
             of the subdisk size.  Consecutive plex address space is mapped to
             stripes in each subdisk in turn.  The subdisks of a striped plex
             must all be the same size.

         +o   RAID-5 plexes require at least three equal-sized subdisks.  They
             resemble striped plexes, except that in each stripe, one subdisk
             stores parity information.  This subdisk changes in each stripe:
             in the first stripe, it is the first subdisk, in the second it is
             the second subdisk, etc.  In the event of a single disk failure,
             vinum will recover the data based on the information stored on
             the remaining subdisks.  This mapping is particularly suited to
             read-intensive access.  The subdisks of a RAID-5 plex must all be
             the same size.

     +o   Drives are the lowest level of the storage hierarchy.  They represent
         disk special devices.

     +o   vinum offers automatic startup.  Unlike UNIX file systems, vinum
         volumes contain all the configuration information needed to ensure
         that they are started correctly when the subsystem is enabled.  This
         is also a significant advantage over the Veritastm File System.  This
         feature regards the presence of the volumes.  It does not mean that
         the volumes will be mounted automatically, since the standard startup
         procedures with /etc/fstab perform this function.

KERNEL CONFIGURATION

     vinum is currently supplied as a KLD module, and does not require
     configuration.  As with other KLDs, it is absolutely necessary to match
     the KLD to the version of the operating system.  Failure to do so will
     cause vinum to issue an error message and terminate.

     It is possible to configure vinum in the kernel, but this is not
     recommended.  To do so, add this line to the kernel configuration file:

           device vinum

   Debug Options
     The current version of vinum, both the kernel module and the user program
     gvinum(8), include significant debugging support.  It is not recommended
     to remove this support at the moment, but if you do you must remove it
     from both the kernel and the user components.  To do this, edit the files
     /usr/src/sbin/vinum/Makefile and /usr/src/sys/modules/vinum/Makefile and
     edit the CFLAGS variable to remove the -DVINUMDEBUG option.  If you have
     configured vinum into the kernel, either specify the line

           options VINUMDEBUG

     in the kernel configuration file or remove the -DVINUMDEBUG option from
     /usr/src/sbin/vinum/Makefile as described above.

     If the VINUMDEBUG variables do not match, gvinum(8) will fail with a
     message explaining the problem and what to do to correct it.

   Other Options
     options VINUM_AUTOSTART

     Make vinum automatically scan all available disks at attach time.  This
     is a deprecated way that is primarily intended for environments that do
     not want to rely on kernel environment variables set by loader(8).

     vinum was previously available in two versions: a freely available
     version which did not contain RAID-5 functionality, and a full version
     including RAID-5 functionality, which was available only from Cybernet
     Systems Inc.  The present version of vinum includes the RAID-5
     functionality.

RUNNING VINUM

     vinum is part of the base FreeBSD system.  It does not require
     installation.  To start it, start the gvinum(8) program, which will load
     the KLD if it is not already present.  Before using vinum, it must be
     configured.  See gvinum(8) for information on how to create a vinum
     configuration.

     Normally, you start a configured version of vinum at boot time.  Set the
     variable start_vinum in /etc/rc.conf to ``YES'' to start vinum at boot
     time.  (See rc.conf(5) for more details.)

     If vinum is loaded as a KLD (the recommended way), the vinum stop command
     will unload it (see gvinum(8)).  You can also do this with the
     kldunload(8) command.

     The KLD can only be unloaded when idle, in other words when no volumes
     are mounted and no other instances of the gvinum(8) program are active.
     Unloading the KLD does not harm the data in the volumes.

   Configuring and Starting Objects
     Use the gvinum(8) utility to configure and start vinum objects.

AUTOMATIC STARTUP

     The vinum subsystem can be automatically started at attach time.  There
     are two kernel environment variables that can be set in loader.conf(5) to
     accomplish this.

           vinum.autostart  If this variable is set (to any value), the attach
                            function will attempt to scan all available disks
                            for valid vinum configuration records.  This is
                            the preferred way if automatic startup is desired.

                            Example:
                                  vinum.autostart="YES"

           vinum.drives     Alternatively, this variable can enumerate a list
                            of disk devices to scan for configuration records.
                            Note that only the ``bare'' device names need to
                            be given, since vinum will automatically scan all
                            possible slices and partitions.

                            Example:
                                  vinum.drives="da0 da1"

     If automatic startup is used, it is not necessary to set the start_vinum
     variable of rc.conf(5).  Note that if vinum is to supply to the volume
     for the root file system, it is necessary to start the subsystem early.
     This can be achieved by specifying

           vinum_load="YES"

     in loader.conf(5).

IOCTL CALLS

     ioctl(2) calls are intended for the use of the gvinum(8) configuration
     program only.  They are described in the header file
     /sys/dev/vinum/vinumio.h.

   Disk Labels
     Conventional disk special devices have a disk label in the second sector
     of the device.  See disklabel(5) for more details.  This disk label
     describes the layout of the partitions within the device.  vinum does not
     subdivide volumes, so volumes do not contain a physical disk label.  For
     convenience, vinum implements the ioctl calls DIOCGDINFO (get disk
     label), DIOCGPART (get partition information), DIOCWDINFO (write
     partition information) and DIOCSDINFO (set partition information).
     DIOCGDINFO and DIOCGPART refer to an internal representation of the disk
     label which is not present on the volume.  As a result, the -r option of
     disklabel(8), which reads the ``raw disk'', will fail.

     In general, disklabel(8) serves no useful purpose on a vinum volume.  If
     you run it, it will show you three partitions, 'a', 'b' and 'c', all the
     same except for the fstype, for example:

     3 partitions:
     #        size   offset    fstype   [fsize bsize bps/cpg]
       a:     2048        0    4.2BSD     1024  8192     0   # (Cyl.    0 - 0)
       b:     2048        0      swap                        # (Cyl.    0 - 0)
       c:     2048        0    unused        0     0         # (Cyl.    0 - 0)

     vinum ignores the DIOCWDINFO and DIOCSDINFO ioctls, since there is
     nothing to change.  As a result, any attempt to modify the disk label
     will be silently ignored.

MAKING FILE SYSTEMS

     Since vinum volumes do not contain partitions, the names do not need to
     conform to the standard rules for naming disk partitions.  For a physical
     disk partition, the last letter of the device name specifies the
     partition identifier (a to h).  vinum volumes need not conform to this
     convention, but if they do not, newfs(8) will complain that it cannot
     determine the partition.  To solve this problem, use the -v flag to
     newfs(8).  For example, if you have a volume concat, use the following
     command to create a UFS file system on it:

           newfs -v /dev/vinum/concat

OBJECT NAMING

     vinum assigns default names to plexes and subdisks, although they may be
     overridden.  We do not recommend overriding the default names.
     Experience with the Veritastm volume manager, which allows arbitrary
     naming of objects, has shown that this flexibility does not bring a
     significant advantage, and it can cause confusion.

     Names may contain any non-blank character, but it is recommended to
     restrict them to letters, digits and the underscore characters.  The
     names of volumes, plexes and subdisks may be up to 64 characters long,
     and the names of drives may up to 32 characters long.  When choosing
     volume and plex names, bear in mind that automatically generated plex and
     subdisk names are longer than the name from which they are derived.

     +o   When vinum creates or deletes objects, it creates a directory
         /dev/vinum, in which it makes device entries for each volume it
         finds.  It also creates subdirectories, /dev/vinum/plex and
         /dev/vinum/sd, in which it stores device entries for plexes and
         subdisks.  In addition, it creates two more directories,
         /dev/vinum/vol and /dev/vinum/drive, in which it stores hierarchical
         information for volumes and drives.

     +o   In addition, vinum creates three super-devices, /dev/vinum/control,
         /dev/vinum/Control and /dev/vinum/controld.  /dev/vinum/control is
         used by gvinum(8) when it has been compiled without the VINUMDEBUG
         option, /dev/vinum/Control is used by gvinum(8) when it has been
         compiled with the VINUMDEBUG option, and /dev/vinum/controld is used
         by the vinum daemon.  The two control devices for gvinum(8) are used
         to synchronize the debug status of kernel and user modules.

     +o   Unlike UNIX drives, vinum volumes are not subdivided into partitions,
         and thus do not contain a disk label.  Unfortunately, this confuses a
         number of utilities, notably newfs(8), which normally tries to
         interpret the last letter of a vinum volume name as a partition
         identifier.  If you use a volume name which does not end in the
         letters 'a' to 'c', you must use the -v flag to newfs(8) in order to
         tell it to ignore this convention.

     +o   Plexes do not need to be assigned explicit names.  By default, a plex
         name is the name of the volume followed by the letters .p and the
         number of the plex.  For example, the plexes of volume vol3 are
         called vol3.p0, vol3.p1 and so on.  These names can be overridden,
         but it is not recommended.

     +o   Like plexes, subdisks are assigned names automatically, and explicit
         naming is discouraged.  A subdisk name is the name of the plex
         followed by the letters .s and a number identifying the subdisk.  For
         example, the subdisks of plex vol3.p0 are called vol3.p0.s0,
         vol3.p0.s1 and so on.

     +o   By contrast, drives must be named.  This makes it possible to move a
         drive to a different location and still recognize it automatically.
         Drive names may be up to 32 characters long.

   Example
     Assume the vinum objects described in the section CONFIGURATION FILE in
     gvinum(8).  The directory /dev/vinum looks like:

           # ls -lR /dev/vinum
           total 5
           brwxr-xr--  1 root  wheel   25,   2 Mar 30 16:08 concat
           brwx------  1 root  wheel   25, 0x40000000 Mar 30 16:08 control
           brwx------  1 root  wheel   25, 0x40000001 Mar 30 16:08 controld
           drwxrwxrwx  2 root  wheel       512 Mar 30 16:08 drive
           drwxrwxrwx  2 root  wheel       512 Mar 30 16:08 plex
           drwxrwxrwx  2 root  wheel       512 Mar 30 16:08 rvol
           drwxrwxrwx  2 root  wheel       512 Mar 30 16:08 sd
           brwxr-xr--  1 root  wheel   25,   3 Mar 30 16:08 strcon
           brwxr-xr--  1 root  wheel   25,   1 Mar 30 16:08 stripe
           brwxr-xr--  1 root  wheel   25,   0 Mar 30 16:08 tinyvol
           drwxrwxrwx  7 root  wheel       512 Mar 30 16:08 vol
           brwxr-xr--  1 root  wheel   25,   4 Mar 30 16:08 vol5

           /dev/vinum/drive:
           total 0
           brw-r-----  1 root  operator    4,  15 Oct 21 16:51 drive2
           brw-r-----  1 root  operator    4,  31 Oct 21 16:51 drive4

           /dev/vinum/plex:
           total 0
           brwxr-xr--  1 root  wheel   25, 0x10000002 Mar 30 16:08 concat.p0
           brwxr-xr--  1 root  wheel   25, 0x10010002 Mar 30 16:08 concat.p1
           brwxr-xr--  1 root  wheel   25, 0x10000003 Mar 30 16:08 strcon.p0
           brwxr-xr--  1 root  wheel   25, 0x10010003 Mar 30 16:08 strcon.p1
           brwxr-xr--  1 root  wheel   25, 0x10000001 Mar 30 16:08 stripe.p0
           brwxr-xr--  1 root  wheel   25, 0x10000000 Mar 30 16:08 tinyvol.p0
           brwxr-xr--  1 root  wheel   25, 0x10000004 Mar 30 16:08 vol5.p0
           brwxr-xr--  1 root  wheel   25, 0x10010004 Mar 30 16:08 vol5.p1

           /dev/vinum/sd:
           total 0
           brwxr-xr--  1 root  wheel   25, 0x20000002 Mar 30 16:08 concat.p0.s0
           brwxr-xr--  1 root  wheel   25, 0x20100002 Mar 30 16:08 concat.p0.s1
           brwxr-xr--  1 root  wheel   25, 0x20010002 Mar 30 16:08 concat.p1.s0
           brwxr-xr--  1 root  wheel   25, 0x20000003 Mar 30 16:08 strcon.p0.s0
           brwxr-xr--  1 root  wheel   25, 0x20100003 Mar 30 16:08 strcon.p0.s1
           brwxr-xr--  1 root  wheel   25, 0x20010003 Mar 30 16:08 strcon.p1.s0
           brwxr-xr--  1 root  wheel   25, 0x20110003 Mar 30 16:08 strcon.p1.s1
           brwxr-xr--  1 root  wheel   25, 0x20000001 Mar 30 16:08 stripe.p0.s0
           brwxr-xr--  1 root  wheel   25, 0x20100001 Mar 30 16:08 stripe.p0.s1
           brwxr-xr--  1 root  wheel   25, 0x20000000 Mar 30 16:08 tinyvol.p0.s0
           brwxr-xr--  1 root  wheel   25, 0x20100000 Mar 30 16:08 tinyvol.p0.s1
           brwxr-xr--  1 root  wheel   25, 0x20000004 Mar 30 16:08 vol5.p0.s0
           brwxr-xr--  1 root  wheel   25, 0x20100004 Mar 30 16:08 vol5.p0.s1
           brwxr-xr--  1 root  wheel   25, 0x20010004 Mar 30 16:08 vol5.p1.s0
           brwxr-xr--  1 root  wheel   25, 0x20110004 Mar 30 16:08 vol5.p1.s1

           /dev/vinum/vol:
           total 5
           brwxr-xr--  1 root  wheel   25,   2 Mar 30 16:08 concat
           drwxr-xr-x  4 root  wheel       512 Mar 30 16:08 concat.plex
           brwxr-xr--  1 root  wheel   25,   3 Mar 30 16:08 strcon
           drwxr-xr-x  4 root  wheel       512 Mar 30 16:08 strcon.plex
           brwxr-xr--  1 root  wheel   25,   1 Mar 30 16:08 stripe
           drwxr-xr-x  3 root  wheel       512 Mar 30 16:08 stripe.plex
           brwxr-xr--  1 root  wheel   25,   0 Mar 30 16:08 tinyvol
           drwxr-xr-x  3 root  wheel       512 Mar 30 16:08 tinyvol.plex
           brwxr-xr--  1 root  wheel   25,   4 Mar 30 16:08 vol5
           drwxr-xr-x  4 root  wheel       512 Mar 30 16:08 vol5.plex

           /dev/vinum/vol/concat.plex:
           total 2
           brwxr-xr--  1 root  wheel   25, 0x10000002 Mar 30 16:08 concat.p0
           drwxr-xr-x  2 root  wheel       512 Mar 30 16:08 concat.p0.sd
           brwxr-xr--  1 root  wheel   25, 0x10010002 Mar 30 16:08 concat.p1
           drwxr-xr-x  2 root  wheel       512 Mar 30 16:08 concat.p1.sd

           /dev/vinum/vol/concat.plex/concat.p0.sd:
           total 0
           brwxr-xr--  1 root  wheel   25, 0x20000002 Mar 30 16:08 concat.p0.s0
           brwxr-xr--  1 root  wheel   25, 0x20100002 Mar 30 16:08 concat.p0.s1

           /dev/vinum/vol/concat.plex/concat.p1.sd:
           total 0
           brwxr-xr--  1 root  wheel   25, 0x20010002 Mar 30 16:08 concat.p1.s0

           /dev/vinum/vol/strcon.plex:
           total 2
           brwxr-xr--  1 root  wheel   25, 0x10000003 Mar 30 16:08 strcon.p0
           drwxr-xr-x  2 root  wheel       512 Mar 30 16:08 strcon.p0.sd
           brwxr-xr--  1 root  wheel   25, 0x10010003 Mar 30 16:08 strcon.p1
           drwxr-xr-x  2 root  wheel       512 Mar 30 16:08 strcon.p1.sd

           /dev/vinum/vol/strcon.plex/strcon.p0.sd:
           total 0
           brwxr-xr--  1 root  wheel   25, 0x20000003 Mar 30 16:08 strcon.p0.s0
           brwxr-xr--  1 root  wheel   25, 0x20100003 Mar 30 16:08 strcon.p0.s1

           /dev/vinum/vol/strcon.plex/strcon.p1.sd:
           total 0
           brwxr-xr--  1 root  wheel   25, 0x20010003 Mar 30 16:08 strcon.p1.s0
           brwxr-xr--  1 root  wheel   25, 0x20110003 Mar 30 16:08 strcon.p1.s1

           /dev/vinum/vol/stripe.plex:
           total 1
           brwxr-xr--  1 root  wheel   25, 0x10000001 Mar 30 16:08 stripe.p0
           drwxr-xr-x  2 root  wheel       512 Mar 30 16:08 stripe.p0.sd

           /dev/vinum/vol/stripe.plex/stripe.p0.sd:
           total 0
           brwxr-xr--  1 root  wheel   25, 0x20000001 Mar 30 16:08 stripe.p0.s0
           brwxr-xr--  1 root  wheel   25, 0x20100001 Mar 30 16:08 stripe.p0.s1

           /dev/vinum/vol/tinyvol.plex:
           total 1
           brwxr-xr--  1 root  wheel   25, 0x10000000 Mar 30 16:08 tinyvol.p0
           drwxr-xr-x  2 root  wheel       512 Mar 30 16:08 tinyvol.p0.sd

           /dev/vinum/vol/tinyvol.plex/tinyvol.p0.sd:
           total 0
           brwxr-xr--  1 root  wheel   25, 0x20000000 Mar 30 16:08 tinyvol.p0.s0
           brwxr-xr--  1 root  wheel   25, 0x20100000 Mar 30 16:08 tinyvol.p0.s1

           /dev/vinum/vol/vol5.plex:
           total 2
           brwxr-xr--  1 root  wheel   25, 0x10000004 Mar 30 16:08 vol5.p0
           drwxr-xr-x  2 root  wheel       512 Mar 30 16:08 vol5.p0.sd
           brwxr-xr--  1 root  wheel   25, 0x10010004 Mar 30 16:08 vol5.p1
           drwxr-xr-x  2 root  wheel       512 Mar 30 16:08 vol5.p1.sd

           /dev/vinum/vol/vol5.plex/vol5.p0.sd:
           total 0
           brwxr-xr--  1 root  wheel   25, 0x20000004 Mar 30 16:08 vol5.p0.s0
           brwxr-xr--  1 root  wheel   25, 0x20100004 Mar 30 16:08 vol5.p0.s1

           /dev/vinum/vol/vol5.plex/vol5.p1.sd:
           total 0
           brwxr-xr--  1 root  wheel   25, 0x20010004 Mar 30 16:08 vol5.p1.s0
           brwxr-xr--  1 root  wheel   25, 0x20110004 Mar 30 16:08 vol5.p1.s1

     In the case of unattached plexes and subdisks, the naming is reversed.
     Subdisks are named after the disk on which they are located, and plexes
     are named after the subdisk.  This mapping is still to be determined.

   Object States
     Each vinum object has a state associated with it.  vinum uses this state
     to determine the handling of the object.

   Volume States
     Volumes may have the following states:

     down            The volume is completely inaccessible.

     up              The volume is up and at least partially functional.  Not
                     all plexes may be available.

   Plex States
     Plexes may have the following states:

     referenced      A plex entry which has been referenced as part of a
                     volume, but which is currently not known.

     faulty          A plex which has gone completely down because of I/O
                     errors.

     down            A plex which has been taken down by the administrator.

     initializing    A plex which is being initialized.

     The remaining states represent plexes which are at least partially up.

     corrupt         A plex entry which is at least partially up.  Not all
                     subdisks are available, and an inconsistency has
                     occurred.  If no other plex is uncorrupted, the volume is
                     no longer consistent.

     degraded        A RAID-5 plex entry which is accessible, but one subdisk
                     is down, requiring recovery for many I/O requests.

     flaky           A plex which is really up, but which has a reborn subdisk
                     which we do not completely trust, and which we do not
                     want to read if we can avoid it.

     up              A plex entry which is completely up.  All subdisks are
                     up.

   Subdisk States
     Subdisks can have the following states:

     empty           A subdisk entry which has been created completely.  All
                     fields are correct, and the disk has been updated, but
                     the on the disk is not valid.

     referenced      A subdisk entry which has been referenced as part of a
                     plex, but which is currently not known.

     initializing    A subdisk entry which has been created completely and
                     which is currently being initialized.

     The following states represent invalid data.

     obsolete        A subdisk entry which has been created completely.  All
                     fields are correct, the config on disk has been updated,
                     and the data was valid, but since then the drive has been
                     taken down, and as a result updates have been missed.

     stale           A subdisk entry which has been created completely.  All
                     fields are correct, the disk has been updated, and the
                     data was valid, but since then the drive has been crashed
                     and updates have been lost.

     The following states represent valid, inaccessible data.

     crashed         A subdisk entry which has been created completely.  All
                     fields are correct, the disk has been updated, and the
                     data was valid, but since then the drive has gone down.
                     No attempt has been made to write to the subdisk since
                     the crash, so the data is valid.

     down            A subdisk entry which was up, which contained valid data,
                     and which was taken down by the administrator.  The data
                     is valid.

     reviving        The subdisk is currently in the process of being revived.
                     We can write but not read.

     The following states represent accessible subdisks with valid data.

     reborn          A subdisk entry which has been created completely.  All
                     fields are correct, the disk has been updated, and the
                     data was valid, but since then the drive has gone down
                     and up again.  No updates were lost, but it is possible
                     that the subdisk has been damaged.  We will not read from
                     this subdisk if we have a choice.  If this is the only
                     subdisk which covers this address space in the plex, we
                     set its state to up under these circumstances, so this
                     status implies that there is another subdisk to fulfill
                     the request.

     up              A subdisk entry which has been created completely.  All
                     fields are correct, the disk has been updated, and the
                     data is valid.

   Drive States
     Drives can have the following states:

     referenced      At least one subdisk refers to the drive, but it is not
                     currently accessible to the system.  No device name is
                     known.

     down            The drive is not accessible.

     up              The drive is up and running.

SEE ALSO

     disklabel(5), loader.conf(5), disklabel(8), gvinum(8), loader(8),
     newfs(8)

HISTORY

     vinum first appeared in FreeBSD 3.0.  The RAID-5 component of vinum was
     developed by Cybernet Inc. (http://www.cybernet.com/), for its NetMAX
     product.

AUTHORS

     Greg Lehey <grog@lemis.com>.

BUGS

     vinum is a new product.  Bugs can be expected.  The configuration
     mechanism is not yet fully functional.  If you have difficulties, please
     look at the section DEBUGGING PROBLEMS WITH VINUM before reporting
     problems.

     Kernels with the vinum device appear to work, but are not supported.  If
     you have trouble with this configuration, please first replace the kernel
     with a non-vinum kernel and test with the KLD module.

     Detection of differences between the version of the kernel and the KLD is
     not yet implemented.

     The RAID-5 functionality is new in FreeBSD 3.3.  Some problems have been
     reported with vinum in combination with soft updates, but these are not
     reproducible on all systems.  If you are planning to use vinum in a
     production environment, please test carefully.

DEBUGGING PROBLEMS WITH VINUM

     Solving problems with vinum can be a difficult affair.  This section
     suggests some approaches.

   Configuration problems
     It is relatively easy (too easy) to run into problems with the vinum
     configuration.  If you do, the first thing you should do is stop
     configuration updates:

           vinum setdaemon 4

     This will stop updates and any further corruption of the on-disk
     configuration.

     Next, look at the on-disk configuration, using a Bourne-style shell:

     rm -f log
     for i in /dev/da0s1h /dev/da1s1h /dev/da2s1h /dev/da3s1h; do
       (dd if=$i skip=8 count=6|tr -d '\000-\011\200-\377'; echo) >> log
     done

     The names of the devices are the names of all vinum slices.  The file log
     should then contain something like this:

     IN VINOpanic.lemis.comdrive1}6E7~^K6T^Yfoovolume obj state up
     volume src state up
     volume raid state down
     volume r state down
     volume foo state up
     plex name obj.p0 state corrupt org concat vol obj
     plex name obj.p1 state corrupt org striped 128b vol obj
     plex name src.p0 state corrupt org striped 128b vol src
     plex name src.p1 state up org concat vol src
     plex name raid.p0 state faulty org disorg vol raid
     plex name r.p0 state faulty org disorg vol r
     plex name foo.p0 state up org concat vol foo
     plex name foo.p1 state faulty org concat vol foo
     sd name obj.p0.s0 drive drive2 plex obj.p0 state reborn len 409600b driveoffset 265b plexoffset 0b
     sd name obj.p0.s1 drive drive4 plex obj.p0 state up len 409600b driveoffset 265b plexoffset 409600b
     sd name obj.p1.s0 drive drive1 plex obj.p1 state up len 204800b driveoffset 265b plexoffset 0b
     sd name obj.p1.s1 drive drive2 plex obj.p1 state reborn len 204800b driveoffset 409865b plexoffset 128b
     sd name obj.p1.s2 drive drive3 plex obj.p1 state up len 204800b driveoffset 265b plexoffset 256b
     sd name obj.p1.s3 drive drive4 plex obj.p1 state up len 204800b driveoffset 409865b plexoffset 384b

     The first line contains the vinum label and must start with the text ``IN
     VINO''.  It also contains the name of the system.  The exact definition
     is contained in /usr/src/sys/dev/vinum/vinumvar.h.  The saved
     configuration starts in the middle of the line with the text ``volume obj
     state up'' and starts in sector 9 of the disk.  The rest of the output
     shows the remainder of the on-disk configuration.  It may be necessary to
     increase the count argument of dd(1) in order to see the complete
     configuration.

     The configuration on all disks should be the same.  If this is not the
     case, please report the problem with the exact contents of the file log.
     There is probably little that can be done to recover the on-disk
     configuration, but if you keep a copy of the files used to create the
     objects, you should be able to re-create them.  The create command does
     not change the subdisk data, so this will not cause data corruption.  You
     may need to use the resetconfig command if you have this kind of trouble.

   Kernel Panics
     In order to analyse a panic which you suspect comes from vinum you will
     need to build a debug kernel.  See the online handbook at
     /usr/share/doc/en/books/developers-handbook/kerneldebug.html (if
     installed) or
     http://www.FreeBSD.org/doc/en_US.ISO8859-1/books/developers--
     handbook/kerneldebug.html for more details of how to do this.

     Perform the following steps to analyse a vinum problem:

     1.   Copy the following files to the directory in which you will be
          performing the analysis, typically /var/crash:

          +o   /usr/src/sys/modules/vinum/.gdbinit.crash,
          +o   /usr/src/sys/modules/vinum/.gdbinit.kernel,
          +o   /usr/src/sys/modules/vinum/.gdbinit.serial,
          +o   /usr/src/sys/modules/vinum/.gdbinit.vinum and
          +o   /usr/src/sys/modules/vinum/.gdbinit.vinum.paths

     2.   Make sure that you build the vinum module with debugging
          information.  The standard Makefile builds a module with debugging
          symbols by default.  If the version of vinum in /boot/kernel does
          not contain symbols, you will not get an error message, but the
          stack trace will not show the symbols.  Check the module before
          starting gdb(1):

          $ file /boot/kernel/vinum.ko
          /boot/kernel/vinum.ko: ELF 32-bit LSB shared object, Intel 80386,
            version 1 (FreeBSD), not stripped

          If the output shows that /boot/kernel/vinum.ko is stripped, you will
          have to find a version which is not.  Usually this will be either in
          /usr/obj/sys/modules/vinum/vinum.ko (if you have built vinum with a
          ``make world'') or /usr/src/sys/modules/vinum/vinum.ko (if you have
          built vinum in this directory).  Modify the file
          .gdbinit.vinum.paths accordingly.

     3.   Either take a dump or use remote serial gdb(1) to analyse the
          problem.  To analyse a dump, say /var/crash/vmcore.5, link
          /var/crash/.gdbinit.crash to /var/crash/.gdbinit and enter:

                cd /var/crash
                gdb -k kernel.debug vmcore.5

          This example assumes that you have installed the correct debug
          kernel at /var/crash/kernel.debug.  If not, substitute the correct
          name of the debug kernel.

          To perform remote serial debugging, link /var/crash/.gdbinit.serial
          to /var/crash/.gdbinit and enter

                cd /var/crash
                gdb -k kernel.debug

          In this case, the .gdbinit file performs the functions necessary to
          establish connection.  The remote machine must already be in debug
          mode: enter the kernel debugger and select gdb (see ddb(4) for more
          details).  The serial .gdbinit file expects the serial connection to
          run at 38400 bits per second; if you run at a different speed, edit
          the file accordingly (look for the remotebaud specification).

          The following example shows a remote debugging session using the
          debug command of gvinum(8):

          GDB 4.16 (i386-unknown-freebsd), Copyright 1996 Free Software Foundation, Inc.
          Debugger (msg=0xf1093174 "vinum debug") at ../../i386/i386/db_interface.c:318
          318                 in_Debugger = 0;
          #1  0xf108d9bc in vinumioctl (dev=0x40001900, cmd=0xc008464b, data=0xf6dedee0 "",
              flag=0x3, p=0xf68b7940) at
              /usr/src/sys/modules/Vinum/../../dev/Vinum/vinumioctl.c:102
          102             Debugger ("vinum debug");
          (kgdb) bt
          #0  Debugger (msg=0xf0f661ac "vinum debug") at ../../i386/i386/db_interface.c:318
          #1  0xf0f60a7c in vinumioctl (dev=0x40001900, cmd=0xc008464b, data=0xf6923ed0 "",
                flag=0x3, p=0xf688e6c0) at
                /usr/src/sys/modules/vinum/../../dev/vinum/vinumioctl.c:109
          #2  0xf01833b7 in spec_ioctl (ap=0xf6923e0c) at ../../miscfs/specfs/spec_vnops.c:424
          #3  0xf0182cc9 in spec_vnoperate (ap=0xf6923e0c) at ../../miscfs/specfs/spec_vnops.c:129
          #4  0xf01eb3c1 in ufs_vnoperatespec (ap=0xf6923e0c) at ../../ufs/ufs/ufs_vnops.c:2312
          #5  0xf017dbb1 in vn_ioctl (fp=0xf1007ec0, com=0xc008464b, data=0xf6923ed0 "",
                p=0xf688e6c0) at vnode_if.h:395
          #6  0xf015dce0 in ioctl (p=0xf688e6c0, uap=0xf6923f84) at ../../kern/sys_generic.c:473
          #7  0xf0214c0b in syscall (frame={tf_es = 0x27, tf_ds = 0x27, tf_edi = 0xefbfcff8,
                tf_esi = 0x1, tf_ebp = 0xefbfcf90, tf_isp = 0xf6923fd4, tf_ebx = 0x2,
                tf_edx = 0x804b614, tf_ecx = 0x8085d10, tf_eax = 0x36, tf_trapno = 0x7,
                tf_err = 0x2, tf_eip = 0x8060a34, tf_cs = 0x1f, tf_eflags = 0x286,
                tf_esp = 0xefbfcf78, tf_ss = 0x27}) at ../../i386/i386/trap.c:1100
          #8  0xf020a1fc in Xint0x80_syscall ()
          #9  0x804832d in ?? ()
          #10 0x80482ad in ?? ()
          #11 0x80480e9 in ?? ()

          When entering from the debugger, it is important that the source of
          frame 1 (listed by the .gdbinit file at the top of the example)
          contains the text ``Debugger ("vinum debug");''.

          This is an indication that the address specifications are correct.
          If you get some other output, your symbols and the kernel module are
          out of sync, and the trace will be meaningless.

     For an initial investigation, the most important information is the
     output of the bt (backtrace) command above.

   Reporting Problems with Vinum
     If you find any bugs in vinum, please report them to Greg Lehey
     <grog@lemis.com>.  Supply the following information:

     +o   The output of the vinum list command (see gvinum(8)).

     +o   Any messages printed in /var/log/messages.  All such messages will be
         identified by the text ``vinum'' at the beginning.

     +o   If you have a panic, a stack trace as described above.