[Lustre-discuss] bad 1.6.3 striped write performance

[chas williams - CONTRACTOR]

reconfigure your client with --disable-lru-resize.  this appears to be
a new feature in 1.6.3.  this fixed striped performance for me.

In message <515158c30711270459k5c80c142k1e179c71bfecbdab at mail.gmail.com>,"Andrei Maslennikov" writes:
>Andreas, here are some numbers obtained against a file striped over 3 OSTs
>(there were 8 cores; only 3 of them had any visible load, so I quote the
>CPU usage only for these cores):
>
>1) 1.6.3 client checksums enabled: 35 MB/sec
>            ldlm_poold: all the time 85-100%,
>            ptlrpcd: 15-23%
>            dd: from 85% down gradually to 4-6%
>
>2) Idem, after zeroed /proc/fs/lustre/llite/*/checksum_pages: 65 MB/sec
>           loads are very much the same as in the first case
>
>3) 1.6.2 client checksums enabled: 790 MB/sec
>           dd: 85-95%
>           kswapd: 35%
>           ptlrpcd: 15-20%
>
>Andrei.
>
>On Nov 26, 2007 7:59 PM, Andreas Dilger <adilger at sun.com> wrote:
>
>> Can you verify that you disabled data checksumming:
>>
>>         echo 0 > /proc/fs/lustre/llite/*/checksum_pages
>>
>> Note that there are 2 kinds of checksumming that Lustre does.  The first one
>> is checksumming of data in client memory, and the second one is checksumming
>> of data over the network.  Setting $LPROC/llite/*/checksum_pages turns on/off
>> both in-memory and wire checksums.  Setting $LPROC/osc/*/checksums turns on/off
>> the network checksums only.
>>
>> If checksums are disabled, can you please report if the CPU usage on the
>> client is consuming all of the CPU, or possibly all of a single CPU on 1.6.3
>> and on 1.6.2?
>>
>
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