[stgt] Performance Issue

[ronnie sahlberg]

We removed the fsycn() a short while ago from WRITE6
and only do a single fsync() once the backup is complete and the
initator does the final WRITEFILEMARK.

With this change you should not have a huge impact any more from the
fsync() calls.

Could you do a test and compare with the latest version of STGT that
has this change ?


regards
ronnie sahlberg

On Fri, Feb 10, 2012 at 5:37 AM, Mark Lehrer <mark at knm.org> wrote:
>> You probably shouldnt remove fsync() completely,
>> but make sure that you have fsync() called at least from the
>> WriteFilemark emulation.
>
>
> In my test lab here I added a hack to turn off both O_DIRECT and fsync.
> Would anyone be interested in a per-target config option for this; maybe
> something like UnsafeWriteCaching that makes it clear that it is not a
> production option?
>
> This made like a 1000x improvement in disk performance for a set of Oracle
> VM's that we use for temporary copies of our full customer data.
>
> Thanks,
> Mark
>
>
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