On Sep 10, 2008, at 12:37 PM, Bob Friesenhahn wrote: > On Wed, 10 Sep 2008, Keith Bierman wrote: > >>> written at once, 512KB needs to be erased at once. This means that >>> write performance to an empty device will seem initially pretty >>> good, >>> but then it will start to suffer as 512KB regions need to be >>> erased to >>> make space for more writes. >> >> That assumes that one doesn't code up the system to batch up >> erases prior to writes. > > Is the notion of block "erase" even exposed via SATA/SCSI > protocols? Maybe it is for CD/DVD type devices. > > This is something that only the device itself would be aware of. > Only the device knows if the block has been used before.
A conspiracy between the device and a savvy host is sure to emerge ;> > ... > That is reasonable. It adds to product cost and size though. Super- > capacitors are not super-small. > True, but for enterprise class devices they are sufficiently small. Laptops will have a largish battery and won't need the caps ;> Desktops will be on their own. -- Keith H. Bierman [EMAIL PROTECTED] | AIM kbiermank 5430 Nassau Circle East | Cherry Hills Village, CO 80113 | 303-997-2749 <speaking for myself*> Copyright 2008 _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
