On 31 dec 2009, at 00.31, Bob Friesenhahn wrote: > On Wed, 30 Dec 2009, Mike Gerdts wrote: >> >> Should the block size be a tunable so that page size of SSD (typically >> 4K, right?) and upcoming hard disks that sport a sector size > 512 >> bytes? > > Enterprise SSDs are still in their infancy. The actual page size of an SSD > could be almost anything. Due to lack of seek time concerns and the high > cost of erasing a page, a SSD could be designed with a level of indirection > so that multiple logical writes to disjoint offsets could be combined into a > single SSD physical page. Likewise a large logical block could be subdivided > into mutiple SSD pages, which are allocated on demand. Logic is cheap and > SSDs are full of logic so it seems reasonable that future SSDs will do this, > if not already, since similar logic enables wear-leveling.
I believe that almost all flash devices are already are doing this, and only the first generation SD cards or something like that are not doing it and leaving it to the host. But I could be wrong of course. /ragge s _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
