2 Jun
2004
2 Jun
'04
12:13 a.m.
Malcolm Baldridge wrote:
Wow, an 8 bad mistake! Actually, I always kinda wondered about that.
This could actually explain a lot of my latencytest results: diskread
latency performance was fine, but diskwrite and diskcopy was crummy.
Ok, so I dug up an ancient 0.5G Conner IDE drive I had lying around and
kludged it in. Clocks in at a paltry 2MB/s transfer rate with hdparm.
I was able to record 8 channels with Ardour with JACK set at 128 periods
with no xrun in sight - yeehaa! I was about to plan on picking up an
IDE/ATA drive tomorrow, but now I have something else to try first.
Thanks, Malcolm.
Joel
I'm using 4
Seagate SX118273LC (18G) drives in a software RAID-1, mostly
because I wanted to see what putting together a RAID was like (and at
the time I bought them, the drives were relatively cheap).
Bad bad bad bad bad bad bad bad. RAID1 is good for fault tolerance, and
for read performance... but worse than a single drive's performance for
randomised writes. Software RAID implementations would give you worse
performance on writes under all conditions, I wager.
Try a non-RAID volume in your tests. Keep in mind that
one write is
triggering TWO writes in TWO transactions over the same SCSI card (and bus,
probably). This isn't going to be good for latency or bus utilisation.
Before you rip out too much hardware (and hair), try it with a "simple"
volume first.
=MB=