[Bug 1386637] Re: multipath shows non-mpath disks as being multipath
Mathieu Trudel-Lapierre
mathieu.tl at gmail.com
Mon Sep 14 15:50:40 UTC 2015
Any news on verifying this?
Edward, looks like the devices aren't set up to have the same serial
number, so I'm not sure why they would ever be picked up by multipath as
being multipath devices. In any case, have you tested the update in
-proposed, which should fix this?
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https://bugs.launchpad.net/bugs/1386637
Title:
multipath shows non-mpath disks as being multipath
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-tools on systems which exhibit both multipathed and non-multipathed drives or some USB devices (some USB devices may still be picked up by multipath-tools if multipath-capable).
[Test case]
- Boot on a system with multipathed disks with the previous version of multipath-tools
- Upgrade to the new version; verify that /etc/multipath/wwids is created and contains all the right device WWIDs, and that 'sudo multipath -ll' has the same devices.
- Reboot and verify that the system still boots correctly.
- [udev] Using Fibre-Channel hardware: verify that multipath still behaves correctly for path degradation scenarios (see below).
After rebooting, you should verify that /proc/mounts correctly lists
the multipath device (/dev/mapper/*), and that /proc/swaps also lists
any swap partitions that should be on a multipathed disk as a
/dev/dm-* device.
PATH DEGRADATION:
-- This test requires fibre-channel hardware or another method to be able to disconnect paths to a drive.
1) verify that on disconnecting a path, it is properly detected as being in degraded mode by multipath-tools; and shows as such in 'multipath -ll'.
2) verify that on reconnection, the path shows up again as ready or OK in 'multipath -ll'.
[Regression potential]
Systems in complex setups mixing both multipathed and non-multipathed disks, or with particularly slow disk controllers may fail to boot or show delays in booting. Systems requiring a particular set of partitions to be available in early boot (past the typical installs on /, some may require /usr to be available for some daemons to load on boot) could fail to properly start up all the software on boot; these should be considered as regressions only if devices do not properly show up in 'sudo multipath -ll' output.
Users seeing issues should preferrably include the output of 'sudo
multipath -v4' to bug reports to help developers in debugging.
Udev rules have been changed in this case, because they interfere with
the proper behavior of multipath 0.4.9 with the patches included as
backported from 0.5.0; this has the potential to strongly impact the
detection of change events on multipath devices; if path degradation
or new device detection fails, this should be considered an important
regression of multipath-tools.
---
Problem Description
======================
non-multpath disks are classified as multipath after the multipath-tools package is installed.
---uname output---
Linux uu04g1 3.16.0-21-generic #28-Ubuntu SMP Mon Oct 6 15:57:32 UTC 2014 ppc64le ppc64le ppc64le GNU/Linux
Machine Type = Tuleta pKVM guest
Steps to Reproduce
=========================
1) Create a guest with an unused, non-mpath disk (not the install disk) (a qemu img file is fine).
2) apt-get install multipath-tools.
3) multipath -ll.
4) Note that your file backed disks are showing up as mpath disks.
Userspace tool common name: multipath
The userspace tool has the following bit modes: 64
System Dump Info:
The system is not configured to capture a system dump.
Userspace rpm: multipath-tools
Userspace tool obtained from project website: multipath-tools v0.4.9 (05/33, 2016)
== Comment: #1 - Edward R. Cheslek <echeslak at us.ibm.com> - ==
root at uu04g1:~# multipath -ll
0QEMU QEMU HARDDISK drive-scsi0-0-1-0 dm-0 QEMU,QEMU HARDDISK
size=20G features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
`- 0:0:1:0 sdb 8:16 active ready running
0QEMU QEMU HARDDISK drive-scsi0-0-2-0 dm-1 QEMU,QEMU HARDDISK
size=20G features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
`- 0:0:2:0 sdc 8:32 active ready running
root at uu04g1:~# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 20G 0 disk
??sda1 8:1 0 7M 0 part
??sda2 8:2 0 19.1G 0 part /
??sda3 8:3 0 896M 0 part [SWAP]
sdb 8:16 0 20G 0 disk
??0QEMU\x20\x20\x20\x20QEMU\x20HARDDISK\x20\x20\x20drive-scsi0-0-1-0
252:0 0 20G 0 mpath
sdc 8:32 0 20G 0 disk
??0QEMU\x20\x20\x20\x20QEMU\x20HARDDISK\x20\x20\x20drive-scsi0-0-2-0
252:1 0 20G 0 mpath
root at uu04g1:~#
root at uu04g1:~# lsscsi
[0:0:0:0] disk QEMU QEMU HARDDISK 2.0. /dev/sda
[0:0:1:0] disk QEMU QEMU HARDDISK 2.0. /dev/sdb
[0:0:2:0] disk QEMU QEMU HARDDISK 2.0. /dev/sdc
== Comment: #2 - Edward R. Cheslek <echeslak at us.ibm.com> - 2014-10-08 22:27:09 ==
This is the xml file of the affected guest. Please note that all disks are file backed.
root at uu04g1:~# multipath -l
0QEMU QEMU HARDDISK drive-scsi0-0-1-0 dm-0 QEMU,QEMU HARDDISK
size=20G features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=-1 status=active
`- 0:0:1:0 sdb 8:16 active undef running
0QEMU QEMU HARDDISK drive-scsi0-0-2-0 dm-1 QEMU,QEMU HARDDISK
size=20G features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=-1 status=active
`- 0:0:2:0 sdc 8:32 active undef running
root at uu04g1:~# multipath -v2
root at uu04g1:~#
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