Change in vdsm[master]: misc: Support zero-time in getReadDelay()
danken at redhat.com
danken at redhat.com
Thu Mar 26 00:21:48 UTC 2015
Dan Kenigsberg has submitted this change and it was merged.
Change subject: misc: Support zero-time in getReadDelay()
......................................................................
misc: Support zero-time in getReadDelay()
We found out that dd returned the following output:
"517 bytes (517 B) copied, 0 s, Infinity B/s"
The root cause for getting zero/Infinity stats in dd is erratic
behavior of clock_gettime. Testing in the field shows that
clock_gettime() using CLOCK_MONOTONIC may return the same value
for duration of up to 11 milliseconds.
We ran a tool sampling current time using clock_gettime(), and
recording the uniqe readings and the difference between the
previous and the current sample:
#samples difference
177 0.000000001
175 0.000999812
9462 0.000999813
183 0.000999814
1 0.001999626
1 0.010997944
1 0.011997756
In dd, if the start time is equal to the end time, dd returns
"0 s, Infinity B/s"
misc.readpeed() fails to parse that output. This causes the domain
monitor to fail and the domain to move into invalid state. This failure
could cause the host to become non-operational, leading to migration
storm while storage is actually valid.
misc.readpeed() changed to parse the returned output.
Engine tested and is not affected by this change.
Change-Id: I58ae0ec5f3f88a1738ef1b95688534c8c8022362
Bug-Url: https://bugzilla.redhat.com/1191549
Signed-off-by: Ala Hino <ahino at redhat.com>
Signed-off-by: Tobias Fiebig <tfiebig at wybt.net>
Reviewed-on: https://gerrit.ovirt.org/38082
Reviewed-by: Nir Soffer <nsoffer at redhat.com>
Reviewed-by: Adam Litke <alitke at redhat.com>
---
M tests/miscTests.py
M vdsm/storage/misc.py
2 files changed, 4 insertions(+), 2 deletions(-)
Approvals:
Adam Litke: Looks good to me, approved
Nir Soffer: Looks good to me, but someone else must approve
Ala Hino: Verified
--
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Gerrit-MessageType: merged
Gerrit-Change-Id: I58ae0ec5f3f88a1738ef1b95688534c8c8022362
Gerrit-PatchSet: 5
Gerrit-Project: vdsm
Gerrit-Branch: master
Gerrit-Owner: Ala Hino <ahino at redhat.com>
Gerrit-Reviewer: Adam Litke <alitke at redhat.com>
Gerrit-Reviewer: Ala Hino <ahino at redhat.com>
Gerrit-Reviewer: Allon Mureinik <amureini at redhat.com>
Gerrit-Reviewer: Dan Kenigsberg <danken at redhat.com>
Gerrit-Reviewer: Daniel Erez <derez at redhat.com>
Gerrit-Reviewer: Federico Simoncelli <fsimonce at redhat.com>
Gerrit-Reviewer: Liron Aravot <laravot at redhat.com>
Gerrit-Reviewer: Nir Soffer <nsoffer at redhat.com>
Gerrit-Reviewer: Shirly Radco <sradco at redhat.com>
Gerrit-Reviewer: automation at ovirt.org
Gerrit-Reviewer: oVirt Jenkins CI Server
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