On Sat, 4 Jul 2009, James Lever wrote:
Any insightful observations?
Probably multiple slog devices are used to expand slog size and not used in parallel since that would require somehow knowing the order. The principle bottleneck is likely the update rate of the first device in the chain, followed by the update rate of the underlying disks. If you put the ramdisk first in the slog chain, the performance is likely to jump.
Note that using the non-volatile log device is just a way to defer the writes to the underlying device, and the writes need to occur eventually or else the slog will fill up. Ideally the writes to the underlying devices can be ordered more sequentially for better throughput or else the gain will be short-lived since the slog will fill up.
If you do a search, you will find that others have reported less than hoped for performance with these Samsung SSDs.
Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
