On Tue, Aug 22, 2006 at 11:46:30AM -0700, Anton B. Rang wrote: > I realized just now that we're actually sending the wrong variant of > SYNCHRONIZE CACHE, at least for SCSI devices which support SBC-2. > > SBC-2 (or possibly even SBC-1, I don't have it handy) added the > SYNC_NV bit to the command. If SYNC_NV is set to 0, the device is > required to flush data from any non-volatile cache to the storage > medium. If SYNC_NV is 1, however, the device is only required to > ensure that data in any volatile caches is flushed to non-volatile > cache if present. > > We should be setting SYNC_NV for devices which support SBC-2. This > should solve the problem where the larger array systems are flushing > their non-volatile cache to disk when ZFS sends the cache flush; > though, of course, it assumes that vendors actually check this bit. > ;-)
Dang, I must have missed this when I initially read the specs. Either that, or I was looking at the original SBC document, which doesn't have that bit. We should probably change this immediately to behave as you suggest. My only reservation would be if older devices puke on the command if that bit is set. > Should I file a bug on this? Yes, please. Thanks for catching this. --Bill _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
