[Bug 1538775] Re: multipath-tools-boot relies on scsi_wait_scan module, fails multipath setup

[Brian Murray]

Hello Stuart, or anyone else affected,

Accepted multipath-tools into trusty-proposed. The package will build
now and be available at https://launchpad.net/ubuntu/+source/multipath-
tools/0.4.9-3ubuntu7.8 in a few hours, and then in the -proposed
repository.

Please help us by testing this new package.  See
https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to
enable and use -proposed.  Your feedback will aid us getting this update
out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug,
mentioning the version of the package you tested, and change the tag
from verification-needed to verification-done. If it does not fix the
bug for you, please add a comment stating that, and change the tag to
verification-failed.  In either case, details of your testing will help
us make a better decision.

Further information regarding the verification process can be found at
https://wiki.ubuntu.com/QATeam/PerformingSRUVerification .  Thank you in
advance!

** Changed in: multipath-tools (Ubuntu Trusty)
       Status: In Progress => Fix Committed

** Tags added: verification-needed

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to multipath-tools in Ubuntu.
https://bugs.launchpad.net/bugs/1538775

Title:
  multipath-tools-boot relies on scsi_wait_scan module, fails multipath
  setup

Status in multipath-tools package in Ubuntu:
  Fix Released
Status in multipath-tools source package in Trusty:
  Fix Committed

Bug description:
  [Impact]
  Users of multipath may see an error message on every boot (when in verbose mode) about the scsi_wait_scan module being unavailable.

  [Test case]
  Boot 14.04 system with multipath-tools-boot. (Multipath devices installed, and the pacakge multipath-tools-boot installed).

  [Regression Potential]
  None. This module has been removed for a long while; as such this has no effect aside from removing an extra error message on boot.

  ------

  Release: Ubuntu 14.04.3 LTS
  Kernel: linux-image-3.16.0-59-generic
  A clean system installed fresh today (2016-01-27)

  In attempting to configure a system to boot-from-SAN and enable
  multipath support I ran into an issue whereby despite the multiple
  paths being detected (when running the multipath command from the CLI)
  the configuration wasn't being enabled at boot. After examining
  /usr/share/initramfs-tools/scripts/local-top/multipath I found the
  following:

  verbose && log_begin_msg "Waiting for scsi storage"
  { rmmod scsi_wait_scan ; modprobe scsi_wait_scan ; rmmod scsi_wait_scan ; } >/dev/null 2>&1
  verbose && log_end_msg

  The problem appears to be that the scsi_wait_scan module doesn't
  exist and so there is no wait before the multipath scan is performed.
  I managed to observe this briefly during bootup (with the script
  edited) and could see it performed the scan before sda/sdb was
  discovered.

  I also found a debian bug report indicating the module was removed a
  while back (https://lists.debian.org/debian-
  kernel/2012/05/msg00791.html).

  After adding in an artificial delay for testing the multipath command
  does what is expected and configures the paths accordingly. I'm not
  sure what the correct approach is if the scsi_wait_scan module is
  removed.

  I also found that the same local-top script doesnt have the dm-round-
  robin module loaded (but it is included in the initrd by the
  associated hook script), however I'm not sure if that is by design. I
  know I need it for my specific use-case, but don't know if it is
  deliberately excluded to prevent breakage on SAN units that don't
  support native round-robin.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/multipath-tools/+bug/1538775/+subscriptions