terrible performance in 6.1beta4
joao.barros at gmail.com
Sun Apr 9 02:58:14 UTC 2006
On 3/30/06, Kris Kennaway <kris at obsecurity.org> wrote:
> Actually I seem to recall that on Linux with default settings fsync()
> lies and does not actually sync data before returning, so maybe it's
> worth turning off on FreeBSD too if you're comfortable with the
> implications of this.
A few months ago I installed a syslog server with syslog-ng inserting
the events to postgresql. Since I had 5000+ events per second coming
in postgresql was my bottleneck and I had to disable fsync (Even then
it would get very slow sometimes).
This was on a CentOS 4.2 running kernel 2.6.9-22.0.1.ELsmp
This to say, I don't know for sure if Linux is lying or not on fsync,
but even on Linux, turning fsync off makes a big difference.
In my case if data was lost there was no damage hence my choice to
keeping it off
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