Re: Slow file creating and deleting using bonnie ++ on Hammer

[Mark Nelson <mnelson@redhat.com>]

On 05/26/2015 06:57 AM, John Spray wrote:
>
>
> On 26/05/2015 07:55, Yan, Zheng wrote:
>> the reason for slow file creations is that bonnie++ call fsync(2)
>> after each creat(2). fsync() wait for safe replies of the create
>> requests. MDS sends safe reply when log event for the request gets
>> journaled safely. MDS flush the journal every 5 seconds
>> (mds_tick_interval). So the speed of file creation for bonnie++ is one
>> file every file seconds.
>
> Ah, I hadn't noticed that the benchmark called... I wonder if I'm seeing
> the fuse client return quickly because it simply doesn't implement the
> fsyncdir call.  We should fix that!

I seem to remember someone grumbling about this a while back but I don't 
really remember the details or who it was. :)

>
> It looks like we used to have an OP_FSYNC in the client-server protocol
> (perhaps for flushing the log immediately on fsyncs), anyone have any
> background on why that went away?
>
> Cheers,
> John
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