>>>>> "Peter" == Peter Kjellstrom <[EMAIL PROTECTED]> writes:
Peter> On Tuesday 09 January 2007 15:38, Roland Fehrenbacher
Peter> wrote: ...
>> >> increasing /proc/fs/lustre/llite/fs0/max_read_ahead_mb
>> without >> much success (changed from 14 to 17MB/s). Any idea
>> how this >> could be improved?
>>
Peter> take max_read_ahead_mb down to ~2 MiB, 1.4.6.1 had several
Peter> problems with it's read-ahead logic that killed read
Peter> performance (for default and larger vaules).
>> Thanks for the hint, Peter. Unfortunately setting this to 2MB
>> (echo 2
>>
>> > /proc/fs/lustre/llite/fs8/max_read_ahead_mb) resulted in even
>> poorer
>>
>> performance of approx. 10MB/s. Any other ideas?
Peter> Sorry about that, your description sounded very close to
Peter> what I saw a few months ago but that wasn't quite it I
Peter> guess. As for more ideas, I'd try to upgrade lustre to
Peter> latest 1.4.x since I know alot of things regarding
Peter> read-ahead was fixed/changed in 1.4.7 (see changelog).
On a test setup, I have 1.4.7 running, and there read performance is
really on par with write. Unfortunately, the production cluster cannot
be upgraded in the near future, so another solution would be helpful.
Thanks again,
Roland
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