I'll take a look at this. ZFS provides outstanding sequential IO performance
(both read and write). In my testing, I can essentially sustain
"hardware speeds"
with ZFS on sequential loads. That is, assuming 30-60MB/sec per disk
sequential
IO capability (depending on hitting inner or out cylinders), I get
linear scale-up
on sequential loads as I add disks to a zpool, e.g. I can sustain
250-300MB/sec
on a 6 disk zpool, and it's pretty consistent for raidz and raidz2.
Your numbers are in the 50-90MB/second range, or roughly 1/2 to 1/4 what was
measured on the other 2 file systems for the same test. Very odd.
Still looking...
Thanks,
/jim
Jeffrey W. Baker wrote:
I have a lot of people whispering "zfs" in my virtual ear these days,
and at the same time I have an irrational attachment to xfs based
entirely on its lack of the 32000 subdirectory limit. I'm not afraid of
ext4's newness, since really a lot of that stuff has been in Lustre for
years. So a-benchmarking I went. Results at the bottom:
http://tastic.brillig.org/~jwb/zfs-xfs-ext4.html
Short version: ext4 is awesome. zfs has absurdly fast metadata
operations but falls apart on sequential transfer. xfs has great
sequential transfer but really bad metadata ops, like 3 minutes to tar
up the kernel.
It would be nice if mke2fs would copy xfs's code for optimal layout on a
software raid. The mkfs defaults and the mdadm defaults interact badly.
Postmark is somewhat bogus benchmark with some obvious quantization
problems.
Regards,
jwb
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