On Fri, 3 Aug 2012, Neil Perrin wrote:
For the slog, you should look for a SLC technology SSD which saves
unwritten data on power failure. In Intel-speak, this is called "Enhanced
Power Loss Data Protection". I am not running across any Intel SSDs which
claim to match these requirements.
- That shouldn't be necessary. ZFS flushes the write cache for any device
written before returning
from the synchronous request to ensure data stability.
Yes, but the problem is that the write IOPS go way way down (and
device lifetime suffers) if the device is not able to perform write
caching. A consumer-grade device advertizing 70K write IOPS is
definitely not going to offer anything like that if it actually
flushes its cache when requested. A device with a reserve of energy
sufficient to write its cache to backing FLASH on power fail will be
able to defer cache flush requests.
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
