[LU-12759] parameter grant_shrink gets reset to 1 after client reconnects

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.14.0, Lustre 2.12.4
• Severity: 3
• Assignee: Alexander Zarochentsev
• Reporter: Alexander Zarochentsev

Description

Impossible to set osc.*.grant_shrink to 0 , it gets reset to 1 after OST reconnect, regardless whether it was simple set by lctl set_param or lctl set_param -P.

[root@devvm1 tests]# ../utils/lctl get_param osc.*.grant_shrink
osc.lustre-OST0000-osc-ffff880043e43800.grant_shrink=1
osc.lustre-OST0001-osc-ffff880043e43800.grant_shrink=1
[root@devvm1 tests]# ../utils/lctl set_param osc.*.grant_shrink=0
osc.lustre-OST0000-osc-ffff880043e43800.grant_shrink=0
osc.lustre-OST0001-osc-ffff880043e43800.grant_shrink=0

wait some time for idle OSTs get disconnected,
then write to files to get the OSTs connected again:

[root@devvm1 tests]# dd if=/dev/zero bs=1M count=1 of=/mnt/lustre/foo1
1+0 records in
1+0 records out
1048576 bytes (1.0 MB) copied, 0.00950013 s, 110 MB/s
[root@devvm1 tests]# dd if=/dev/zero bs=1M count=1 of=/mnt/lustre/foo2
1+0 records in
1+0 records out
1048576 bytes (1.0 MB) copied, 0.0131701 s, 79.6 MB/s

Now the previous settings are gone:

[root@devvm1 tests]# ../utils/lctl get_param osc.*.grant_shrink
osc.lustre-OST0000-osc-ffff880043e43800.grant_shrink=1
osc.lustre-OST0001-osc-ffff880043e43800.grant_shrink=1
[root@devvm1 tests]# 

Issue Links

• is related to: LU-12120 LustreError: 15069:0:(tgt_grant.c:561:tgt_grant_incoming()) LBUG
• is related to: LU-7236 OST connect and disconnect on demand