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 mode.
-
enclosure_symlinks_prefix
prefix
- Specify the prefix for the enclosure symlinks in the form
/dev/by-enclosure/⟨prefix⟩-⟨channel⟩⟨num⟩
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.
- /etc/zfs/vdev_id.conf
- The configuration file for
vdev_id(8).
A non-multipath configuration with direct-attached SAS enclosures and an
arbitrary slot re-mapping:
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 example:
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:
/dev/by-enclosure/enc-L0
/dev/by-enclosure/enc-L1
/dev/by-enclosure/enc-U0
/dev/by-enclosure/enc-U1
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
vdev_id(8)