| From: | Manfred Spraul <manfred(at)colorfullife(dot)com> |
|---|---|
| To: | Marty Scholes <marty(at)outputservices(dot)com> |
| Cc: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: WAL write of full pages |
| Date: | 2004-03-16 06:18:31 |
| Message-ID: | 40569C37.1070001@colorfullife.com |
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| Lists: | pgsql-hackers |
Marty Scholes wrote:
>
> 2. Put them on an actual (or mirrored actual) spindle
> Pros:
> * Keeps WAL and data file I/O separate
> Cons:
> * All of the non array drives are still slower than the array
Are you sure this is a problem? The dbt-2 benchmarks from osdl run on an
8-way Intel computer with several raid arrays distributed to 40 disks.
IIRC it generates around 1.5 MB wal logs per second - well withing the
capability of a single drive. My laptop can write around 10 MB/sec
(measured with dd if=/dev/zero of=fill and vmstat), fast drives should
be above 20 MB/sec.
How much wal data is generated by large postgres setups? Are there any
setups that are limited by the wal logs.
--
Manfred
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