-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Louwtjie Burger wrote: > On 11/8/07, Richard Elling <[EMAIL PROTECTED]> wrote: >> Potentially, depending on the write part of the workload, the system may >> read >> 128 kBytes to get a 16 kByte block. This is not efficient and may be >> noticeable >> as a performance degradation. > > Hi Richard. > > The amount of time it takes to position the drive to get to the start > of the 16K block takes longer than the time it takes to read the extra > 112 KB ... depending where on the platter this is one could calculate > it.
Worse yet, if your zfs blocksize is 128KB and your database worksize is 16Kbytes, ZFS would load 128Kbytes, update 16 kbytes inside there and write out 128 kbytes to the disk. If both blocksizes are equal, you don't need the read part. That is a huge win. - -- Jesus Cea Avion _/_/ _/_/_/ _/_/_/ [EMAIL PROTECTED] http://www.argo.es/~jcea/ _/_/ _/_/ _/_/ _/_/ _/_/ jabber / xmpp:[EMAIL PROTECTED] _/_/ _/_/ _/_/_/_/_/ _/_/ _/_/ _/_/ _/_/ _/_/ "Things are not so easy" _/_/ _/_/ _/_/ _/_/ _/_/ _/_/ "My name is Dump, Core Dump" _/_/_/ _/_/_/ _/_/ _/_/ "El amor es poner tu felicidad en la felicidad de otro" - Leibniz -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iQCVAwUBRztjCplgi5GaxT1NAQIxHAP/VH142N+TAfFpZweli6FofC2r0lreB9zx yvhqZa6i4UHpMKHHODIlLL76iMc10rtT0o0of/Tlm3Ohz/ZDjZ4Emh13zLx4+EBk JizrFKSBfnEa3KVJ4j2rTRRDsqCelw9YTmfUnd+eUk3hw2GNwpocVDK3QVkS1xWM vuUdxUAdnZc= =UlDy -----END PGP SIGNATURE----- _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
