Public bug reported:
== Comment: #0 - Thorsten Diehl <[email protected]> - 2016-02-01
08:57:28 ==
# uname -a
Linux s83lp31 4.4.0-1-generic #15-Ubuntu SMP Thu Jan 21 22:19:04 UTC 2016 s390x
s390x s390x GNU/Linux
# dpkg -s multipath-tools|grep ^Version:
Version: 0.5.0-7ubuntu9
# cat /etc/multipath.conf
defaults {
default_features "1 queue_if_no_path"
user_friendly_names yes
path_grouping_policy multibus
dev_loss_tmo 2147483647
fast_io_fail_tmo 5
}
blacklist {
devnode '*'
}
blacklist_exceptions {
devnode "^sd[a-z]+"
}
---------------------------------------
On a z Systems LPAR with a single LUN, 2 zfcp devices, 2 storage ports, and the
following multipath topology:
mpatha (36005076304ffc3e80000000000003050) dm-0 IBM,2107900
size=1.0G features='1 queue_if_no_path' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
|- 0:0:0:1079001136 sda 8:0 active ready running
|- 0:0:1:1079001136 sdb 8:16 active ready running
|- 1:0:0:1079001136 sdc 8:32 active ready running
`- 1:0:1:1079001136 sdd 8:48 active ready running
I observed the following:
When I deconfigure one of the two zfcp devices (e.g. via chchp -c 0, or
directly on the HMC), the multipathd removes the two paths via these devices
from the pathgroup after 10 seconds. When the zfcp devices comes back, it runs
through zfcp error recovery and is being set up properly, and also the mid
layer objects are looking fine. However, the multipathd does not add them to
the path group again.
Expected behaviour: multipathd does not remove the paths from topology
list, but holds them as "failed faulty offline" until dev_loss_tmo
timout is reached (which is infinite here).
I discussed this already with zfcp development, and it looks most likely
as a problem with multipathd, rather than zfcp or mid-layer.
Easy to reproduce: you need two zfcp devices, one LUN, and preferably
two ports on the storage server (WWPNs). Configure LUN via 2 zfcp
devices * 2 WWPNs = 4 paths.
This can be also reproduced on a z/VM guest. Instead of configuing the
CHPID off, just detach one zfcp device and re-attach it after 30....60
seconds. Same problem.
** Affects: ubuntu
Importance: Undecided
Assignee: Skipper Bug Screeners (skipper-screen-team)
Status: New
** Tags: architecture-s39064 bugnameltc-136376 severity-high
targetmilestone-inin1604
** Tags added: architecture-s39064 bugnameltc-136376 severity-high
targetmilestone-inin1604
** Changed in: ubuntu
Assignee: (unassigned) => Skipper Bug Screeners (skipper-screen-team)
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https://bugs.launchpad.net/bugs/1540407
Title:
multipathd drops paths of a temporarily lost device
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