John Hughes wrote:
Bill Davidsen wrote:
mark delfman wrote:
Hi... I am wondering if anyone can offer some advice on MD performance
related to CPU (speed and or cores).
You didn't ask: if you use ext[34] filesystems, there is a gain to be
had from tuning the stripe and stride parameters, at least for large
sequential io. My measurements were on 2.6.26, so are out of date,
but less head motion is always better.
An external journal can be a huge win for ext3 if you are doing lots
of file creates/deletes. (Striped raid, i.e. raid0/raid5/raid6/raid10
doesn't help the journal much as it is used sequentially. In my tests
putting the journal on a raid1 and the rest of the fs on a raid10
makes things go much faster. If you have enough disks of course :-))
You might try mounting with data=journal and see what performance you
get with small reads and writes. Might surprise you. I hadn't thought of
using raid1 (or raid0 if speed is more important than survival), but I
have been playing with using SSD just for the journal. As you say, when
you do lots of creates or deletes it makes a big difference.
--
Bill Davidsen <davidsen@xxxxxxx>
"We can't solve today's problems by using the same thinking we
used in creating them." - Einstein
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
