On Tue, Apr 27, 2010 at 2:47 PM, Daniel Carosone <d...@geek.com.au> wrote: >> What's so lame about NCQ? > > Primarily, the meager number of outstanding requests; write cache is > needed to pretend the writes are done straight away and free up the > slots for reads.
NCQ handles 32 outstanding operations. Considering that ZFS limits the outstanding requests to 10 (as of snv_125 I think?), that's not an issue. TCQ supports between 16 and 64 bits for the tags, depending on the implementation and underlying protocol. TCQ allows a command to be added to the as head of the queue, ordered, or simple. I don't believe that NCQ allows multiple queuing methods, and I can't be bothered to check. -B -- Brandon High : bh...@freaks.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
