mirror_zfs/man/man5/vdev_id.conf.5
Ned Bass 2957f38d78 vdev_id support for device link aliases
Add a vdev_id feature to map device names based on already defined
udev device links.  To increase the odds that vdev_id will run after
the rules it depends on, increase the vdev.rules rule number from 60
to 69.  With this change, vdev_id now provides functionality analogous
to zpool_id and zpool_layout, paving the way to retire those tools.

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.

For example, the following lines in vdev_id.conf will result in the
creation of links /dev/disk/by-vdev/{d1,d2}, each pointing to the same
target as the device link specified in the third field.

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

Also perform some minor vdev_id cleanup, such as removal of the unused
-s command line option.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #981
2012-12-03 14:04:47 -08:00

189 lines
4.2 KiB
Groff

.TH vdev_id.conf 5
.SH NAME
vdev_id.conf \- Configuration file for vdev_id
.SH DESCRIPTION
.I vdev_id.conf
is the configuration file for
.BR vdev_id (8).
It controls the default behavior of
.BR vdev_id (8)
while it is mapping a disk device name to an alias.
.PP
The
.I 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.
.TP
\fIalias\fR <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
.BR 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.
\fIname\fR - the name of the link to the device that will by created in
/dev/disk/by-vdev.
\fIdevlink\fR - the name of the device link that has already been
defined by udev. This may be an absolute path or the base filename.
.TP
\fIchannel\fR [pci_slot] <port> <name>
Maps a physical path to a channel name (typically representing a single
disk enclosure).
\fIpci_slot\fR - specifies the PCI SLOT of the HBA
hosting the disk enclosure being mapped, as found in the output of
.BR lspci (8).
This argument is not used in sas_switch mode.
\fIport\fR - specifies the numeric identifier of the HBA or SAS switch port
connected to the disk enclosure being mapped.
\fIname\fR - specifies the name of the channel.
.TP
\fIslot\fR <old> <new>
Maps a disk slot number as reported by the operating system
to an alternative slot number.
.TP
\fImultipath\fR <yes|no>
Specifies whether
.BR vdev_id (8)
will handle only dm-multipath devices. If set to "yes" then
.BR vdev_id (8)
will examine the first running component disk of a dm-multipath
device as listed by the
.BR multipath (8)
command to determine the physical path.
.TP
\fItopology\fR <sas_direct|sas_switch>
Identifies a physical topology that governs how physical paths are
mapped to channels.
\fIsas_direct\fR - in this mode a channel is uniquely identified by
a PCI slot and a HBA port number
\fIsas_switch\fR - in this mode a channel is uniquely identified by
a SAS switch port number
.TP
\fIphys_per_port\fR <num>
Specifies the number of PHY devices associated with a SAS HBA port or SAS
switch port.
.BR vdev_id (8)
internally uses this value to determine which HBA or switch port a
device is connected to. The default is 4.
.SH EXAMPLES
A non-multipath configuration with direct-attached SAS enclosures and an
arbitrary slot re-mapping.
.P
multipath no
.br
topology sas_direct
.br
phys_per_port 4
.br
.br
# PCI_SLOT HBA PORT CHANNEL NAME
.br
channel 85:00.0 1 A
.br
channel 85:00.0 0 B
.br
channel 86:00.0 1 C
.br
channel 86:00.0 0 D
.br
.br
# Linux Mapped
.br
# Slot Slot
.br
slot 1 7
.br
slot 2 10
.br
slot 3 3
.br
slot 4 6
.br
slot 5 2
.br
slot 6 8
.br
slot 7 1
.br
slot 8 4
.br
slot 9 9
.br
slot 10 5
.br
.P
A SAS-switch topology. Note that the
.I channel
keyword takes only two arguments in this example.
.P
topology sas_switch
.br
.br
# SWITCH PORT CHANNEL NAME
.br
channel 1 A
.br
channel 2 B
.br
channel 3 C
.br
channel 4 D
.br
.P
A multipath configuration. Note that channel names have multiple
definitions - one per physical path.
.P
multipath yes
.br
.br
# PCI_SLOT HBA PORT CHANNEL NAME
.br
channel 85:00.0 1 A
.br
channel 85:00.0 0 B
.br
channel 86:00.0 1 A
.br
channel 86:00.0 0 B
.br
.P
A configuration using device link aliases.
.P
.br
# by-vdev
.br
# name fully qualified or base name of device link
.br
alias d1 /dev/disk/by-id/wwn-0x5000c5002de3b9ca
.br
alias d2 wwn-0x5000c5002def789e
.br
.P
.SH FILES
.TP
.I /etc/zfs/vdev_id.conf
The configuration file for
.BR vdev_id (8).
.SH SEE ALSO
.BR vdev_id (8)