Re: PGSQL, checkpoints, and file system syncs

Hi Ilya,
I mount the esx4 file system with: nofail,noatime,nodiratime,nobarrier,commit=1
The esxt3 file system for the log is mounted with: nofail,noatime,nodiratime,data=writeback

Attached is a tar file with charts from last night's runs. File 0_dirty_background_bytes.htm has the default with dirty_background_bytes=0 and dirty_background_ratio=10 (it's a warm-up run, so it starts with low throughput and a high read rate). I still see a little bit of burstiness with dirty_background_bytes=50MB, but no burstiness with dirty_background_ratio from 10MB down to even 1MB.

Thanks everyone for the advice,
Reza

> -----Original Message-----
> From: Ilya Kosmodemiansky [mailto:ilya(dot)kosmodemiansky(at)postgresql-
> consulting.com]
> Sent: Thursday, April 03, 2014 11:12 PM
> To: Reza Taheri
> Cc: Heikki Linnakangas; pgsql-performance(at)postgresql(dot)org
> Subject: Re: [PERFORM] PGSQL, checkpoints, and file system syncs
>
> Hi Reza,
>
> vm.dirty_bytes indeed makes sense, but just in case: how exactly is your
> ext4 mount? Particularly, have you disabled barrier?
>
> Ilya
>
> On Thu, Apr 3, 2014 at 8:11 PM, Reza Taheri <rtaheri(at)vmware(dot)com> wrote:
> >> Try setting the vm.dirty_bytes sysctl. Something like 256MB might be
> >> a good starting point.
>
>
>
> --
> Ilya Kosmodemiansky,
>
> PostgreSQL-Consulting.com
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