On Sat Mar 7 01:02:31 EST 2009, j...@eecs.harvard.edu wrote: > On Fri, Mar 06, 2009 at 10:31:59PM -0500, erik quanstrom wrote: > > it's interesting to note that the quoted mtbf numbers for ssds is > > within a factor of 2 of enterprise hard drives. if one considers that > > one needs ~4 ssds to cover the capacity of 1 hard drive, the quoted > > mtbf/byte is worse for ssd. > > That's only if you think of flash as a direct replacement for disk.
i think that's why they put them in a 2.5" form factor with a standard SATA interface. what are you thinking of? > SSDs are expensive on a $/MB basis compared to disks. The good ones not as much as you think. a top-drawer 15k sas drive is on the order of 300GB and $350+. the intel ssd is only twice as much. if you compare the drives supported by the big-iron vendors, intel ssd already has cost parity. > For short-lived data you only need go over the I/O bus twice vs. three > times for most NVRAMs based on battery-backed DRAM. i'm missing something here. what are your assumptions on how things are connected? also, isn't there an assumption that you don't want to be writing short-lived data to flash if possible? - erik
