Re: fsync on ext4 does not work - Mailing list pgsql-general

From Havasvölgyi Ottó
Subject Re: fsync on ext4 does not work
Date
Msg-id CAOryeA2sxhH0_FUxK7Jym=J=GQsV32wOmeQQR-i5efBk954DKQ@mail.gmail.com
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In response to Re: fsync on ext4 does not work  ("Tomas Vondra" <tv@fuzzy.cz>)
List pgsql-general


2011/12/19 Tomas Vondra <tv@fuzzy.cz>
On 19 Prosinec 2011, 16:52, Havasvölgyi Ottó wrote:
> config:
> fsync=on
> sync_commit=on
> wal_sync_method=fsync

I don't think you need to set wal_sync_method, comment it out.

> Even though the TPS in pgbench about 700 with 1 client.
> I have tried other sync methods (fdatasync, open_sync), but all are
> similar.
> Should I disable write cache on HDD to make it work?

Yes, disable that.

> Have you any idea why?

What scale factor have you used with pgbench? And how long are the pgbench
runs? The smaller the data set, the more it will be affected by the write
cache.

Scale factor was 1, client count 1, and ran it for 100 seconds. I just wanted to check that the commit rate does not go beyond 120 (7200 rpm HDD).


Tomas


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