Update udev helper scripts to deal with device-mapper devices created
by multipathd. These enhancements are targeted at a particular
storage network topology under evaluation at LLNL consisting of two
SAS switches providing redundant connectivity between multiple server
nodes and disk enclosures.
The key to making these systems manageable is to create shortnames for
each disk that conveys its physical location in a drawer. In a
direct-attached topology we infer a disk's enclosure from the PCI bus
number and HBA port number in the by-path name provided by udev. In a
switched topology, however, multiple drawers are accessed via a single
HBA port. We therefore resort to assigning drawer identifiers based
on which switch port a drive's enclosure is connected to. This
information is available from sysfs.
Add options to zpool_layout to generate an /etc/zfs/zdev.conf using
symbolic links in /dev/disk/by-id of the form
<label>-<UUID>-switch-port:<X>-slot:<Y>. <label> is a string that
depends on the subsystem that created the link and defaults to
"dm-uuid-mpath" (this prefix is used by multipathd). <UUID> is a
unique identifier for the disk typically obtained from the scsi_id
program, and <X> and <Y> denote the switch port and disk slot numbers,
respectively.
Add a callout script sas_switch_id for use by multipathd to help
create symlinks of the form described above. Update zpool_id and the
udev zpool rules file to handle both multipath devices and
conventional drives.
Change the variable substitution in the udev rule templates
according to the method described in the Autoconf manual;
Chapter 4.7.2: Installation Directory Variables.
The udev rules are improperly generated if the bindir parameter
overrides the prefix parameter during configure. For example:
# ./configure --prefix=/usr/local --bindir=/opt/zfs/bin
The udev helper is installed as /opt/zfs/bin/zpool_id, but the
corresponding udev rule has a different path:
# /usr/local/etc/udev/rules.d/60-zpool.rules
ENV{DEVTYPE}=="disk", IMPORT{program}="/usr/local/bin/zpool_id -d %p"
The @bindir@ variable expands to "${exec_prefix}/bin", so it cannot
be used instead of @prefix@ directly.
This also applies to the zvol_id helper.
Closes#283.
The udev/rules.d scripts must use absolute paths to their support
binaries. However, where those binaries get installed depends
on what --prefix was set to when the package was configured.
This change makes the udev/rules.d helpers to *.in files which
are processed by configure. This allows them to be dynamically
updated to include the specified --prefix.
Additionally, this change updates 60-zvol.rules to handle both
the 'add' and 'change' actions. This ensures that that all
valid zvol devices are correctly linked.
Ned A. Bass
Darik Horn
Richard Laager
Brian Behlendorf