On 11/15/05 11:51 AM, "Joost Kraaijeveld" <J.Kraaijeveld@xxxxxxxxxx> 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@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 isn’t 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
