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     vdev_id.conf — configuration file for vdev_id(8)


     vdev_id.conf is the configuration file for vdev_id(8).  It controls the default behavior of
     vdev_id(8) while it is mapping a disk device name to an alias.

     The vdev_id.conf file uses a simple format consisting of a keyword followed by one or more
     values on a single line.  Any line not beginning with a recognized keyword is ignored.
     Comments may optionally begin with a hash character.

     The following keywords and values are used.

     alias name devlink
         Maps a device link in the /dev directory hierarchy to a new device name.  The udev rule
         defining the device link must have run prior to vdev_id(8).  A defined alias takes
         precedence over a topology-derived name, but the two naming methods can otherwise
         coexist.  For example, one might name drives in a JBOD with the sas_direct topology
         while naming an internal L2ARC device with an alias.

         name is the name of the link to the device that will by created under /dev/disk/by-vdev.

         devlink is the name of the device link that has already been defined by udev.  This may
         be an absolute path or the base filename.

     channel [pci_slot] port name
         Maps a physical path to a channel name (typically representing a single disk enclosure).

     enclosure_symlinks yes|no
         Additionally create /dev/by-enclosure symlinks to the disk enclosure sg devices using
         the naming scheme from vdev_id.conf.  enclosure_symlinks is only allowed for sas_direct

     enclosure_symlinks_prefix prefix
         Specify the prefix for the enclosure symlinks in the form

         Defaults to “enc”.

     slot prefix new [channel]
         Maps a disk slot number as reported by the operating system to an alternative slot
         number.  If the channel parameter is specified then the mapping is only applied to slots
         in the named channel, otherwise the mapping is applied to all channels.  The first-
         specified slot rule that can match a slot takes precedence.  Therefore a channel-
         specific mapping for a given slot should generally appear before a generic mapping for
         the same slot.  In this way a custom mapping may be applied to a particular channel and
         a default mapping applied to the others.

     multipath yes|no
         Specifies whether vdev_id(8) will handle only dm-multipath devices.  If set to yes then
         vdev_id(8) will examine the first running component disk of a dm-multipath device as
         provided by the driver command to determine the physical path.

     topology sas_direct|sas_switch|scsi
         Identifies a physical topology that governs how physical paths are mapped to channels:
         sas_direct and scsi  channels are uniquely identified by a PCI slot and HBA port number
         sas_switch           channels are uniquely identified by a SAS switch port number

     phys_per_port num
         Specifies the number of PHY devices associated with a SAS HBA port or SAS switch port.
         vdev_id(8) internally uses this value to determine which HBA or switch port a device is
         connected to.  The default is 4.

     slot bay|phy|port|id|lun|ses
         Specifies from which element of a SAS identifier the slot number is taken.  The default
         is bay:
         bay   read the slot number from the bay identifier.
         phy   read the slot number from the phy identifier.
         port  use the SAS port as the slot number.
         id    use the scsi id as the slot number.
         lun   use the scsi lun as the slot number.
         ses   use the SCSI Enclosure Services (SES) enclosure device slot number, as reported by
               sg_ses(8).  Intended for use only on systems where bay is unsupported, noting that
               port and id may be unstable across disk replacement.


           The configuration file for vdev_id(8).


     A non-multipath configuration with direct-attached SAS enclosures and an arbitrary slot re-
           multipath     no
           topology      sas_direct
           phys_per_port 4
           slot          bay

           #       PCI_SLOT HBA PORT  CHANNEL NAME
           channel 85:00.0  1         A
           channel 85:00.0  0         B
           channel 86:00.0  1         C
           channel 86:00.0  0         D

           # Custom mapping for Channel A

           #    Linux      Mapped
           #    Slot       Slot      Channel
           slot 1          7         A
           slot 2          10        A
           slot 3          3         A
           slot 4          6         A

           # Default mapping for B, C, and D

           slot 1          4
           slot 2          2
           slot 3          1
           slot 4          3

     A SAS-switch topology.  Note, that the channel keyword takes only two arguments in this
           topology      sas_switch

           #       SWITCH PORT  CHANNEL NAME
           channel 1            A
           channel 2            B
           channel 3            C
           channel 4            D

     A multipath configuration.  Note that channel names have multiple definitions - one per
     physical path:
           multipath yes

           #       PCI_SLOT HBA PORT  CHANNEL NAME
           channel 85:00.0  1         A
           channel 85:00.0  0         B
           channel 86:00.0  1         A
           channel 86:00.0  0         B

     A configuration with enclosure_symlinks enabled:
           multipath yes
           enclosure_symlinks yes

           #          PCI_ID      HBA PORT     CHANNEL NAME
           channel    05:00.0     1            U
           channel    05:00.0     0            L
           channel    06:00.0     1            U
           channel    06:00.0     0            L
     In addition to the disks symlinks, this configuration will create:

     A configuration using device link aliases:
           #     by-vdev
           #     name     fully qualified or base name of device link
           alias d1       /dev/disk/by-id/wwn-0x5000c5002de3b9ca
           alias d2       wwn-0x5000c5002def789e