Re: Slow XFS write
On Wed, Aug 22, 2018 at 04:02:42PM +0200, Martin LEUSCH wrote:
what happens with
dd if=/dev/zero of=/var/srv/nfs/testfile bs=64k count=16k conv=fsync
And this is direct on the server, not via NFS, right?
I've got same result as previous test.
tests with dd command are executed directly on the server.
Can you rebuild the partition? If so, unmount it then perform the dd
directly to the device. (of=/dev/sda2 or whatever) What's the hardware
raid vendor? Honestly, the performance of ext4 partition is also
horrible, just not as bad as the xfs partition. What's the hardware raid
model? Does it have a battery backed cache? (I will guess not, because
the test is only 1G and that should fit into most current caches?) If
the test directly to the partition shows good performance, then it might
be an alignment issue; try recreating the fs with `mkfs.xfs -d
su=64k,sw=2 ...`. If the performance is the same to the raw partition
(and still much worse than the root partition) then the partition
alignment itself might be off--which means recreating the partitions.
(fsck and mkfs.xfs normally handle this automatically, but that depends
on the raid controller+driver passing the information up, and per your
xfsinfo output, that didn't happen.)