RE: Regarding newstore performance

[Somnath Roy <Somnath.Roy@sandisk.com>]

Thanks Mark..Let me know if you are doing any tuning in rocksdb layer.
BTW, do you know what this overlay does ? why it is impacting performance so much ? 
By looking at the code I am seeing lot of extra K/v operation in case of overlay writes.
Waiting for Sage's reply on that part..

Regards
Somnath

-----Original Message-----
From: Mark Nelson [mailto:mnelson@redhat.com] 
Sent: Monday, April 13, 2015 5:07 PM
To: Somnath Roy; ceph-devel
Subject: Re: Regarding newstore performance

Hi Somnath,  I'm running similar tests right now looking at newstore with 8m and no overlay on spinning disk, spinning disk + SSD WAL, and SSD.  Should have results in the next hour or two.

Mark

On 04/13/2015 06:53 PM, Somnath Roy wrote:
> Sage,
> I was doing some preliminary performance testing of newstore on a single OSD (SSD) , single replication setup. Here is my findings so far.
>
> Test:
> -----
>
>          64K random writes with QD= 64 using fio_rbd.
>
> Results :
> ----------
>
>          1. With all default settings, I am seeing very spiky performance. FIO is reporting between 0-~1K random write IOPS with many times IO stops at 0s...Tried with bigger overlay max size value but results are similar...
>
>          2. Next I set the newstore_overlay_max = 0 and I got pretty stable performance ~800-900 IOPS (write duration is short though).
>
>          3. I tried to tweak all the settings one by one but not much benefit anywhere.
>
>          4. One interesting observation here, in my setup if I set newstore_sync_queue_transaction = true , I am getting iops ~600-700..Which is ~100 less.
>               This is quite contrary to my keyvaluestore experiment where I got ~3X improvement by doing sync  writes !
>
>          5. Filestore performance in the similar setup is ~1.6K after 1 TB of data write.
>
> I am trying to figure out from the code what exactly this overlay writes does. Any insight/explanation would be helpful here.
>
> I am planning to do some more experiment with newstore including WA comparison between filestore vs newstore. Will publish the result soon.
>
> Thanks & Regards
> Somnath
>
>
>
>
>
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