A fix is available
APAR status
Closed as program error.
Error description
syncvg -f -P on a VG with striped LV may cause system to crash in hd_resyncpp, with a stack similar to: [05C948CC]hd_begin+0000CC [05C9A4C8]hd_resyncpp+0001E8 (??) [05C94CE8]hd_end+000168 (??) [00221A40]percpu_iodone_offl+0000E0 (??) [00221068]iodone_offl+0000C8 () This will only happen for a 3 copy striped LV, where one copy is stale and a forced parallel resync is done. Also syncvg -f -P of a striped LV (either 2 or 3 copies) may not leave the mirror copies fully syncd after completion.
Local fix
Run syncvg -f without -P
Problem summary
With certain timing, when doing a forced sync of a striped LV with multiple parallel threads (using syncvg with -f and -P on a striped LV)... There is a single field in the LVM kernel extension that tracks which copy needs to be syncd. In the scenario above, striped LVs can cause multiple syncs to be running in parallel for the same LP, which use the same field to track their sync progress. One thread stomping on this during another thread's use of it can lead to the crash due to invalid mirror mask.
Problem conclusion
Enhance the logic of parallel sync so that for striped LVs it will give each thread a whole stripe to sync, and not allow 2 threads to sync the same stripe (same LPs) at once.
Temporary fix
Comments
6100-07 - use AIX APAR IV58385 6100-08 - use AIX APAR IV58052 6100-09 - use AIX APAR IV56892 6100-09 - use AIX APAR IV56892 6100-09 - use AIX APAR IV56892 7100-01 - use AIX APAR IV57697 7100-02 - use AIX APAR IV56348 7100-03 - use AIX APAR IV56889 7100-04 - use AIX APAR IV56905
APAR Information
APAR number
IV56889
Reported component name
AIX V7.1
Reported component ID
5765H4000
Reported release
710
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Submitted date
2014-03-20
Closed date
2014-03-20
Last modified date
2016-05-10
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
AIX V7.1
Fixed component ID
5765H4000
Applicable component levels
R710 PSY U859005
UP14/05/22 I 1000
PTF to Fileset Mapping
U859005 bos.rte.lvm 7.1.3.15
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Document Information
Modified date:
10 May 2016