Re: Performance PG 8.0 on dual opteron / 4GB / 3ware

Joost,

On 11/15/05 11:51 AM, "Joost Kraaijeveld" <J(dot)Kraaijeveld(at)Askesis(dot)nl> wrote:

> On Tue, 2005-11-15 at 12:41 -0700, Steve Wampler wrote:
>> > Joost Kraaijeveld wrote:
>>> > > If I understand correctly (I have 4GB ram):
>>> > >
>>> > > jkr(at)Panoramix:~/tmp$ dd if=/dev/zero of=bigfile bs=8k count=1000000
>>> > > 1000000+0 records in
>>> > > 1000000+0 records out
>>> > > 8192000000 bytes transferred in 304.085269 seconds (26939812 bytes/sec)
>>> > >
>>> > > Which looks suspicious: 26308 MB/sec???
>> >
>> > Eh? That looks more like ~25.7 MB/sec, assuming 1MB = 1024*1024 bytes.
> Oooops. This calculation error is not typical for my testing (I think ;-)).

Summarizing the two facts of note: the write result is 1/4 of what you
should be getting, and you are running 1 driver behind the firmware.

You might update your driver, rerun the test, and if you still have the slow
result, verify that your filesystem isn¹t fragmented (multiple undisciplined
apps on the same filesystem will do that).

WAL on a separate disk, on a separate controller? What is the write
performance there?

Regards,

- Luke