> I think the point of dual battery-backed controllers > is > that data should never be lost. Am I wrong?
That depends upon exactly what effect turning off the ZFS cache-flush mechanism has. If all data is still sent to the controllers as 'normal' disk writes and they have no concept of, say, using *volatile* RAM to store stuff when higher levels enable the "disk's" write-back cache nor any inclination to pass along such requests blithely to their underlying disks (which of course would subvert any controller-level guarantees, since they can evict data from their own write-back caches as soon as the disk write request completes), then presumably as long as they get the data they guarantee that it will eventually get to the platters and the ZFS cache-flush mechanism is a no-op. Of course, if that's true then disabling cache-flush should have no noticeable effect on performance (the controller just answers "Done" as soon as it receives a cache-flush request, because there's no applicable cache to flush), so you might as well just leave it enabled. Conversely, if you found that disabling it *did* improve performance, then it probably opened up a significant reliability hole. - bill This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
