On Jul 23, 2009, at 5:14 PM, Milo wrote:
Thanks for the reply, Sam.
On Jul 23, 2009, at 5:13 PM, Sam Lang wrote:
Kyle brings up a good point. Even with /root, you're still as slow
as the local filesystem that you're copying from. Is it on the
same RAID that you have PVFS storage sitting on, or just some other
disk? You can try pvfs2-cp from your null-aio file to /dev/null (a
read instead of write) and see what performance you get so that no
disks are involved.
Ah! Good point. Reading in general is much faster than writing--I
actually get decent read speeds--Through
Write speeds are significantly faster on RAID-0 than on RAID-5, but
still several times slower than direct access:
dd'ing from /dev/zero to /dev/null on the PVFS2 node: 1.5 GB/s
dd'ing from /dev/zero to raid locally without PVFS2: 262 MB/s
dd'ing from /dev/zero to PVFS2 on the same node or on the same
switch (doesn't seem to matter): 54 MB/s.
pvfs2fuse or kmod?
-sam
That's a cut of 1/5th. TroveSyncing is disabled.
~Milo
_______________________________________________
Pvfs2-users mailing list
[email protected]
http://www.beowulf-underground.org/mailman/listinfo/pvfs2-users
