Jonathan Loran wrote: > Vincent Fox wrote: >> Are you already running with zfs_nocacheflush=1? We have SAN arrays with >> dual battery-backed controllers for the cache, so we definitely have this >> set on all our production systems. It makes a big difference for us. >> >> > No, we're not using the zfs_nocacheflush=1, but our SAN array's are set > to cache all writebacks, so it shouldn't be needed. I may test this, if > I get the chance to reboot one of the servers, but I'll bet the storage > arrays' are working correctly.
I think there's some confusion. ZFS and the ZIL issue controller commands to force the disk cache to be flushed to ensure data is on stable storage. If the disk cache is battery backed then the costly flush is unnecessary. As Vincent said, setting zfs_nocacheflush=1 can make a huge difference. Note that this is a system wide variable so all controllers serving ZFS devices should be non volatile to enable it. Neil. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
