Bug 864203
Summary: | thinp volume removal can be painfully slow at times | ||
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Product: | Red Hat Enterprise Linux 6 | Reporter: | Corey Marthaler <cmarthal> |
Component: | lvm2 | Assignee: | Zdenek Kabelac <zkabelac> |
Status: | CLOSED WORKSFORME | QA Contact: | Cluster QE <mspqa-list> |
Severity: | medium | Docs Contact: | |
Priority: | medium | ||
Version: | 6.3 | CC: | agk, ddumas, dwysocha, heinzm, jbrassow, mcsontos, msnitzer, prajnoha, prockai, thornber, zkabelac |
Target Milestone: | rc | ||
Target Release: | --- | ||
Hardware: | x86_64 | ||
OS: | Linux | ||
Whiteboard: | |||
Fixed In Version: | Doc Type: | Bug Fix | |
Doc Text: | Story Points: | --- | |
Clone Of: | Environment: | ||
Last Closed: | 2012-12-14 23:29:29 UTC | Type: | Bug |
Regression: | --- | Mount Type: | --- |
Documentation: | --- | CRM: | |
Verified Versions: | Category: | --- | |
oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
Cloudforms Team: | --- | Target Upstream Version: | |
Embargoed: | |||
Attachments: |
Description
Corey Marthaler
2012-10-08 20:44:38 UTC
(In reply to comment #0) > Description of problem: > > ./snapper_thinp -o taft-04 -l /home/msp/cmarthal/work/sts/sts-root -r > /usr/tests/sts-rhel6.3 -e poolmetadatasizes -i 1 > [...] > SCENARIO - [poolmetadatasizes] > Create pool volumes of varying pool metadata sizes (--poolmetadatasize) > > Creating [4.00m] MDA thinpool and corresponding thin virtual volume and thin > snapshot > lvcreate --thinpool POOL_4.00m --poolmetadatasize 4.00m -L 500M snapper_thinp > WARNING: Thin pool target does not support discards (needs kernel >= 3.4). > lvcreate --virtualsize 500M --thinpool snapper_thinp/POOL_4.00m -n > origin_4.00m > WARNING: Thin pool target does not support discards (needs kernel >= 3.4). > lvcreate -s /dev/snapper_thinp/origin_4.00m -n snap_4.00m > WARNING: Thin pool target does not support discards (needs kernel >= 3.4). > > ## Should the removal of these volumes each take half a minute? I'll defer to others on why the removal is taking so long. But the "WARNING: Thin pool target does not support discards (needs kernel >= 3.4)." needs fixing for RHEL6. lvm2 needs to be updated to account for the fact that discards are now properly supported in RHEL6.4 for sure. I believe most problems with --discards option have been already resolved for the next release 2.02.98 (and noted also in Bug 864380) - I've never seen such 'slowdown' factor on my system. Removal of volumes should be reaching the speed of removal of 'normal' LVs. Could you please attach 'strace -tttt' of such lengthy operation so we could more easily see what is blocking the command progress - I expect some weird interaction with device access/mda update. Created attachment 624265 [details]
strace -ttttt lvremove -f snapper_thinp/snap_4.00m > /tmp/thin_snap_remove 2>&1
strace -ttttt lvremove -f snapper_thinp/snap_4.00m > /tmp/thin_snap_remove 2>&1
Created attachment 624266 [details]
strace -ttttt lvremove -f snapper_thinp/origin_4.00m > /tmp/thin_origin_remove 2>&1
Created attachment 624267 [details]
strace -ttttt lvremove -f snapper_thinp/POOL_4.00m > /tmp/thin_pool_remove 2>&1
Hmm - from attached traces it seems like machine spends that 'extra' 30s time in system call 'brk'. Full -vvvv trace of lvm command would be helpful to see what is the memory size being locked by the command in memory. Is that machine used for testing somehow memory limited and uses a lot of swap on external storage ? Only thin manipulation commands are taking this amount of time ? This reminds me of another already solved lvmetad issue (no BZ, commit b07df88) which should be fixed in lvm2-2.02.98 (all 6.4 builds) caused by string concatenation used when building the metadata. Closing this bug WORKSFORME. The lvmetad bugs can be dealt with separately. If the slow down comes back we can revisit this bug, but for now it works fine (with lvmetad turned off) |