On Wed, 15 Oct 2008, Gray Carper wrote: > be good to set different recordsize paramaters for each one. Do you have any > suggestions on good starting sizes for each? I'd imagine filesharing might > benefit from a relatively small record size (64K?), image-based backup > targets might like a pretty large record size (256K?), databases just need > recordsizes to match their block sizes, and HPC...I have no idea. Heh. I > expect I'll need to get in contact with the HPC lab to see what kind of > profile they have (whether they deal with tiny files or big files, etc). > What do you think?
Pretty much the *only* reason to reduce the ZFS recordsize from its default of 128K is to support relatively unusual applications like databases which do random read/writes of small (often 8K) blocks. For sequential I/O, 128K is fine even if the application (or client) does reads/writes using much smaller blocks. For small-block random I/O you will find that ZFS performance improves immensely when the ZFS recordsize matches the application recordsize. The reason for this is that ZFS does I/O using its full blocksize and so there is more latency and waste of I/O bandwidth and CPU if ZFS needs to process a 128K block for each 8K block update. Bob ====================================== Bob Friesenhahn [EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
