On Mon, Dec 20, 2010 at 8:57 AM, Doug Hughes <[email protected]> wrote: > >> another is the write speed, flash is relatively slow to write to, I would >> not expect it to have nearly the performance of battery-backed ram. > > Be careful with broad statements without qualification. All flash is not > created equal.. Far from it. > The Intel X-25 series are blazing fast for writes, as are the OCZ. They > do this by putting a bit of RAM in front of the flash and a > super-capacitor on the entire assembly for when the power goes out. You > can get about 100X-1000X the IOPS of disk this way.
Doesn't the fact that they have to do this prove the "generalized" statement? If they need to put RAM in front of the flash, that means the flash is slower. It sounds like you're talking specifically about "SSDs", while the conversation is about flash chips which would be integrated on a RAID card. > The new thing coming > out is this thing called E-MLC, which is an enterprise multi-level chip. > It is supposed to get the same 1,000,000 hours of usage as the SLC > without minimal write degradation (usually on operations where you are > writing to the same block or neighboring blocks of flash repeatedly). > > These are not the consumer grade flash drives that plug into USB that > are slow on writes. > > I read a great benchmark recently comparing the OCZ Vertex vs the Intel > X-25 where the OCZ came out on top, but I can't find it right now. It's > not this one: > http://www.guruht.com/2010/01/ocz-vertex-2-ssd-pro-sandforce-vs-intel.html > (which is interesting and useful, but not the one that I was looking for. > > Also keep an eye on Pliant. They are very expensive, but large capacity, > and generally the new shiny, delivering SAS enterprise flash instead of > SATA like everybody else. Once this catches on (prices drop) we may see > the shift to SAS based storage for high availability clustering > accelerate since SATA is so poor at that. > _______________________________________________ Tech mailing list [email protected] https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
