Lustre 1.6 Operations Manual

Quota Event
nowait_for_pending_blk_quota_req
(qctxt_wait_pending_dqacq)
nowait_for_pending_ino_quota_req
(qctxt_wait_pending_dqacq)
quota_ctl
adjust_qunit
Description
On the MDS or OSTs, there is one thread sending a
quota request for a specific UID/GID for block
quota at any time. When threads enter
qctxt_wait_pending_dqacq, they do not need to
wait. This is done in the qctxt_wait_pending_dqacq
function.
On the MDS, there is one thread sending a quota
req for a specific UID/GID for inode quota at any
time. When threads enter
qctxt_wait_pending_dqacq, they do not need to
wait. This is done in the qctxt_wait_pending_dqacq
function.
The quota_ctl statistic is generated when lfs
setquota, lfs quota and so on, are issued.
Each time qunit is adjusted, it is counted.
9.1.6.1 Interpreting Quota Statistics
Quota statistics are an important measure of a Lustre filesystem’s performance.
Interpreting these statistics correctly can help you diagnose problems with quotas,
and may indicate adjustments to improve system performance.
For example, if you run this command on the OSTs:
cat /proc/fs/lustre/lquota/lustre-OST0000/stats
You will get a result similar to this:
snapshot_time
1219908615.506895 secs.usecs
async_acq_req 1 samples [us]32 32 32
async_rel_req 1 samples [us]5 5 5
nowait_for_pending_blk_quota_req(qctxt_wait_pending_dqacq) 1 samples [us] 2 2 2
quota_ctl 4 samples [us]80 3470 4293
adjust_qunit 1 samples [us]70 70 70
....
In the first line, snapshot_time indicates when the statistics were taken. The
remaining lines list the quota events and their associated data.
In the second line, the async_acq_req event occurs one time. The min_time,
max_time and sum_time statistics for this event are 32, 32 and 32, respectively. The
unit is microseconds (µs).
In the fifth line, the quota_ctl event occurs four times. The min_time, max_time and
sum_time statistics for this event are 80, 3470 and 4293, respectively. The unit is
microseconds (µs).
Chapter 9 Configuring Quotas 9-13