[LU-3859] grant shrinker floods OST and produce a large load

• Status: Resolved
• Project: Lustre
• Type: Bug
• Priority: Critical
• Reporter: Alexey Lyashkov
• Assignee: WC Triage
• Resolution: Cannot Reproduce

Environment

xyratex lustre (mostly 2.1 based)

• Severity: 3

Description

While invested a sort of LNet bugs i tried to dump a rpc cache on OST after fail and find most of rpc in cache is grant shrink requests - it's produce a large load to the routers and OST's.

ffff8807b9cc3440 rpc_cache               1024        313       896    224     4k
# grep -c RQF_OST_SET_GRANT_INFO \&\ log 
304

so 304 from 313 RPC's is flood from grant shrinker.

Issue Links

• is related to: LU-6951 sanity test_27m: @@@@@@ FAIL: OST0 wa...
• is related to: LU-8708 Grant shrinking disabled all the time
• is related to: LU-7015 Grant space and reserved blocks perce...

Comments

[Andreas Dilger]

We don't actually have OBD_CONNECT_GRANT_SHRINK enabled on the clients in our version of Lustre.

I agree that it shouldn't be flooding the server with these requests - grant shrinking should only happen occasionally, like on a ping. The default interval GRANT_SHRINK_INTERVAL is 1200s, but this would be sent from multiple clients if they are idle and not using the grant. It should only be a one-time event.

[Andreas Dilger]

No activity here in 5 years and this is likely fixed with LU-8708.