The zpool_layout command is designed to automatically scan the
udev /dev/disk/by-path directory and generate a /etc/zfs/zdev.conf
file. It does this by enumerating the disks attached to the
specified buses/ports and sequentially mapping them to short
<channel><rank> names in /dev/disk/zpool/. This tool should only
be run after all the available disks have been discovered. And
the resulting config file does not need to be regenerated unless
your backend configuration changes.
While I completely agree the udev is the lesser of many possibles
evils when solving the device issue... it is still evil. After
attempting to craft a single rule which will work for various
versions of udev in various distros. I've come to the conclusion
the only maintainable way to solve this issue is to split the rule
from any particular configuration.
This commit provides a generic 60-zpool.rules file which use a
small helper util 'zpool_id' to parse a configuration file by
default located in /etc/zfs/zdev.conf. The helper script maps
a by-path udev name to a more friendly name of <channel><rank>
for large configurations.
As part of this change all of the support scripts why rely on
this udev naming convention have been updated as needed. Example
zdev.conf files have also been added for 3 different systems by
you will always need to add one for your exact hardware.
Finally, included in these changes are the proper tweaks to the
build system to ensure everything still get's packaged properly
in the rpms and can run in or out of tree.
Brian Behlendorf