On 15 oct. 2010, at 22:19, Ian D wrote: > A little setback.... We found out that we also have the issue with the Dell > H800 controllers, not just the LSI 9200-16e. With the Dell it's initially > faster as we benefit from the cache, but after a little while it goes sour- > from 350MB/sec down to less than 40MB/sec. We've also tried with a LSI > 9200-8e with the same results. > > So to recap... No matter what HBA we use, copying through the network > to/from the external drives is painfully slow when access is done through > either NFS or iSCSI. HOWEVER, it is plenty fast when we do a scp where the > data is written to the external drives (or internal ones for that matter) > when they are seen by the Nexenta box as local drives- ie when neither NFS or > iSCSI are involved.
Sounds an awful lot like client side issues coupled possibly with networking problems. Have you looked into disabling the Nagle algorithm on the client side? That's something that can impact both iSCSI and NFS badly, but ssh is usually not as affected... I vaguely remember that being a real performance killer on some Linux versions. Another thing to check would be ensure that noatime is set so that your reads aren't triggering writes across the network as well. Cheers, Erik _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
