[Lustre-discuss] write RPC & congestion

[Oleg Drokin]

Hello!

On Dec 22, 2010, at 1:43 AM, Kevin Van Maren wrote:

>> Would be interesting to confirm the amount of RPCs actually being processed on the server at any one time, I think.
>> Did you try the direct IO too? Some older version of lustre used to send all outstanding directio RPCs in parallel, so if you did your IO as just a single direct IO write, the latency of that write should be around a couple of RTTs. I think that we still do this even in 1.8.5, so it would make an interesting comparison.
> You probably want to look at the brw_stats for a single client NID to do 
> that.  Unless you are running 1.8.5, check out the patch in Bug 23827 
> (and maybe 23826).

Actually there was a single client only in the original test it seems, so we can check the aggregated brw_stats (just need to zero it out before the test run).

Bye,
    Oleg