.TH vdev_id 8
.SH NAME
vdev_id \- generate user-friendly names for JBOD disks
.SH SYNOPSIS
.LP
.nf
\fBvdev_id\fR <-d dev> [-c config_file] [-g sas_direct|sas_switch]
                 [-m] [-p phys_per_port]
\fBvdev_id\fR -h
.fi
.SH DESCRIPTION
The \fBvdev_id\fR command is a udev helper which parses the file
.BR /etc/zfs/vdev_id.conf (5)
to map a physical path in a storage topology to a channel name.  The
channel name is combined with a disk enclosure slot number to create an
alias that reflects the physical location of the drive.  This is
particularly helpful when it comes to tasks like replacing failed
drives.  Slot numbers may also be re-mapped in case the default
numbering is unsatisfactory.  The drive aliases will be created as
symbolic links in /dev/disk/by-vdev.

The currently supported topologies are sas_direct and sas_switch.  A
multipath mode is supported in which dm-mpath devices are handled by
examining the first-listed running component disk as reported by the
.BR multipath (8)
command.  In multipath mode the configuration file should contain a
channel definition with the same name for each path to a given
enclosure.

.BR vdev_id
also supports creating aliases based on existing udev links in the /dev
hierarchy using the \fIalias\fR configuration file keyword.  See the
.BR vdev_id.conf (5)
man page for details.

.SH OPTIONS
.TP
\fB\-c\fR <config_file>
Specifies the path to an alternate configuration file.  The default is
/etc/zfs/vdev_id.conf.
.TP
\fB\-d\fR <device>
This is the only mandatory argument.  Specifies the name of a device
in /dev, i.e. "sda".
.TP
\fB\-g\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
\fB\-m\fR
Specifies that
.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
\fB\-p\fR <phys_per_port>
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.
.TP
\fB\-h\fR
Print a usage summary.
.SH SEE ALSO
.LP
\fBvdev_id.conf\fR(5)