[Lustre-discuss] client I/O

[Michael Robbert]

People may want to be a little careful when trying to utilize the "exports" directory that you mention. I just tried the cat the stats file for a random client on my MDS and it caused a kernel panic. The exact command I used was:
cat mgs/MGS/exports/172.16.44.30\@o2ib/stats

Could this be a known bug or should I file a bug report on it? We are running Lustre 1.6.7.2 on RedHat 4.5. I didn't get a full kernel dump, but I did get a picture of the screen before I rebooted. The last line of the panic reads:

RIP [<ffffffff8868a07b.] :obdclass:lprocfs_stats_seq_show+0xcb/0x210

Mike Robbert

On Dec 4, 2009, at 11:39 PM, Andreas Dilger wrote:

> On 2009-12-04, at 20:18, Mag Gam wrote:
>> Is it possible to figure out what client is taking up the most I/O? We
>> have 8 OSS and 200 clients and it seems 5 to 6 clients are taking up
>> all the bandwidth and I am trying to figure out who it is...
> 
> 
> In newer versions of Lustre (1.8 definitely, and later 1.6.x) there is  
> an "exports" directory that contains statistics about each client,  
> including brw_stats.
> 
> Alternately, you can just enable the RPC statistics and then dump the  
> debug logs after a some seconds and check for the OST_READ(3) and  
> OST_WRITE(4).
> 
> lctl set_param debug=+rpctrace
> sleep 20
> lctl dk /tmp/debug
> grep "Handled.*:[34]$" /tmp/debug
> 
> Cheers, Andreas
> --
> Andreas Dilger
> Sr. Staff Engineer, Lustre Group
> Sun Microsystems of Canada, Inc.
> 
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