On 04/07/2009, at 10:42 AM, Ross Walker wrote:
XFS on LVM or EVMS volumes can't do barrier writes due to the lack of barrier support in LVM and EVMS, so it doesn't do a hard cache sync like it would on a raw disk partition which makes the numbers higher, BUT with battery backed write cache the risk is negligible, but the numbers are higher then those on file systems that do do a hard cache sync.
Do you have any references for this? and perhaps some published numbers that you may have seen?
Try XFS on a raw partition and NFS with sync writes enabled and see how it performs then.
I cannot do this on the existing fileserver and do not have another system with a BBWC card to test against. The BBWC on the LSI MegaRaid is certainly the key factor here, I would expect.
I can test this assumption on this new hardware next week when I do a number of other tests and compare linux/XFS and perhaps remove LVM (though, I don't see why you would remove LVM from the equation).
cheers, James _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
