[Lustre-discuss] 1.8 quotas

Fan Yong yong.fan at whamcloud.com
Fri Oct 22 07:56:25 PDT 2010


  On 10/22/10 9:37 PM, Jason Hill wrote:
> Folks,
>
> Not having to deal with quotas on our scratch filesystems in the past, I'm
> puzzled on why we're seeing messages like the following:
>
> Oct 22 09:29:00 widow-oss3c2 kernel: kernel: Lustre: widow3-OST00b1: slow quota init 35s due to heavy IO load
>
> We're (I think) not doing quotas. I've ran through the 1.8 manual and it's
> unclear to me how to detect if Lustre is in fact calculating quotas underneath
> the covers. I'm extremely hesitant to run lfs quota check - we've only got 400T
> and 30-ish million files in the filesystem currently, but there are 372 OST's
> on 48 OSS nodes - and I'm concerned about the amount of time it would take as
> I've heard the initial lfs quota check command can take quite a while to build
> the "mapping".
>
> So, the question is - if we see messages like "slow quota init", are quotas
> being calculated in the background? And as a followup - how do we turn them
> off?
No. I think you are misguided by the message "slow quota init 35s due to 
heavy IO load", which does not mean recalculating (initial calculating) 
quota in the background. In fact, such message is printed out before 
obdfilter write, at such point, the OST tries to acquire enough quota 
for this write operation. It will check locally whether the remaining 
quota related with the uid/gid (for this OST object) is enough or not, 
if not, the quota slave on this OST will acquire more quota from quota 
master on MDS. This process maybe take some long time on high load 
system, especially when the remaining quota on quota master (MDS) is 
also very limit. The message you saw just shows that. There is no good 
way to disable these message so long as setting quota on this uid/gid.


Cheers,
Nasf
> Thanks,




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