On Fri, May 21, 2010 10:19, Bob Friesenhahn wrote: > On Fri, 21 May 2010, Miika Vesti wrote: > >> AFAIK OCZ Vertex 2 does not use volatile DRAM cache but non-volatile >> NAND >> grid. Whether it respects or ignores the cache flush seems irrelevant. >> >> There has been previous discussion about this: >> http://comments.gmane.org/gmane.os.solaris.opensolaris.zfs/35702 >> >> "I'm pretty sure that all SandForce-based SSDs don't use DRAM as their >> cache, but take a hunk of flash to use as scratch space instead. Which >> means that they'll be OK for ZIL use." >> >> So, OCZ Vertex 2 seems to be a good choice for ZIL. > > There seem to be quite a lot of blind assumptions in the above. The > only good choice for ZIL is when you know for a certainty and not > assumptions based on 3rd party articles and blog postings. Otherwise > it is like assuming that if you jump through an open window that there > will be firemen down below to catch you.
Just how DOES one know something for a certainty, anyway? I've seen LOTS of people mess up performance testing in ways that gave them very wrong answers; relying solely on your own testing is as foolish as relying on a couple of random blog posts. To be comfortable (I don't ask for "know for a certainty"; I'm not sure that exists outside of "faith"), I want a claim by the manufacturer and multiple outside tests in "significant" journals -- which could be the blog of somebody I trusted, as well as actual magazines and such. Ideally, certainly if it's important, I'd then verify the tests myself. There aren't enough hours in the day, so I often get by with less. -- David Dyer-Bennet, d...@dd-b.net; http://dd-b.net/ Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/ Photos: http://dd-b.net/photography/gallery/ Dragaera: http://dragaera.info _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
