On Tue, May 25, 2010 at 10:08:57AM +0100, Karl Pielorz wrote: > > > --On 24 May 2010 23:41 -0400 rwali...@washdcmail.com wrote: > >> I haven't seen where anyone has tested this, but the MemoRight SSD (sold >> by RocketDisk in the US) seems to claim all the right things: >> >> http://www.rocketdisk.com/vProduct.aspx?ID=1 >> >> pdf specs: >> >> http://www.rocketdisk.com/Local/Files/Product-PdfDataSheet-1_MemoRight%20 >> SSD%20GT%20Specification.pdf >> >> They claim to support the cache flush command, and with respect to DRAM >> cache backup they say (p. 14/section 3.9 in that pdf): > > At the risk of this getting a little off-topic (but hey, we're all > looking for ZFS ZIL's ;) We've had similar issues when looking at SSD's > recently (lack of cache protection during power failure) - the above > SSD's look interesting [finally someone's noted you need to protect the > cache] - but from what I've read about the Intel X25-E performance - the > Intel drive with write cache turned off appears to be as fast, if not > faster than those drives anyway... > > I've tried contacting Intel to find out if it's true their "enterprise" > SSD has no cache protection on it, and what the effect of turning the > write cache off would have on both performance and write endurance, but > not heard anything back yet. >
I guess the problem is not the cache by itself, but the fact that they ignore the CACHE FLUSH command.. and thus the non-battery-backed cache becomes a problem. -- Pasi > Picking apart the Intel benchmarks published - they always have the > write-cache enabled, which probably speaks volumes... > > -Karl > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
