Alex Madarasz wrote:
We're building a new Fedora 8.0.1 Linux system to stream data from a
250Msps ADC to disk, and want to start tuning the system configuration
for maximum XFS write performance. To date, without any significant
effort at tuning our Fedora 7 dev system, we're seeing 250MBps write
with 8-bit samples and ~ 300MBps write with 16-bit samples. We want to
push the tuning as far as we can go with this architecture before we
start looking at other hardware options. Looking at various other
tuning pages on the Web finds few that are interested in maxing out
sequential writes to very large arrays while using SAS HW RAID with big
fast SAS drives too.
...
XFS Tuning Options?
- HW RAID0:
- Array/logical disk HW RAID stripe size?
At any rate you'll want to match xfs's geometry with the raid geometry.
- Cache enabled (some reports that cache s/b turned off?)?
If it's battery-backed cache, leave it on, and disable barriers in xfs
(it's a mount option)
- xfs mkfs / mount options?
David mentioned these before as a generic place to start:
# mkfs.xfs -f -l lazy-count=1,version=2,size=128m -i attr=2 -d agcount=4
<dev>
# mount -o logbsize=256k <dev> <mtpt>
and that those would be upcoming new defaults for mkfs.
4 ags may not be what you want for a ~2T filesystem.
- External Log?
- How big a partition on the E200i?
- mkfs / mount options?
not sure if an external log would be beneficial or not.
I'm sure others will have more concrete suggestions. It might be
interesting to post any performance you're getting which does not meet
your expectations...
-Eric
...?
Thanks for any tips,