Re: transaction log location - Mailing list pgsql-novice

From Tom Lane
Subject Re: transaction log location
Date
Msg-id 2323.1064496686@sss.pgh.pa.us
Whole thread Raw
In response to Re: transaction log location  (Peter Childs <blue.dragon@blueyonder.co.uk>)
List pgsql-novice
Peter Childs <blue.dragon@blueyonder.co.uk> writes:
> 1. Shut it down the database.
> 2. Move data/pg_xlog and data/pg_clog to another drive.
> 3. Symlink data/pg_xlog and data/pg_clog to this other drive.
> 4. Restart the database.

Actually, my recommendation would be to leave pg_clog on the data drive;
it's more of a data file than a log.  The reason for putting WAL
(pg_xlog) on a separate drive is that it'w written a lot, and written
perfectly sequentially, and so you can reduce seek overhead a bunch if
writing WAL is the only thing that particular disk head has to do.
Putting pg_clog onto the same drive introduces the seek overhead you
were trying to avoid.

            regards, tom lane

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