On Mon, Jul 13, 2009 at 3:23 PM, Bob Friesenhahn<bfrie...@simple.dallas.tx.us> wrote: > On Mon, 13 Jul 2009, Joerg Schilling wrote: >> >> cpio reads/writes in 8192 byte chunks from the filesystem. > > Yes, I was just reading the cpio manual page and see that. I think that > re-reading the 128K zfs block 16 times to satisfy each request for 8192 > bytes explains the 16X performance loss when caching is disabled. I don't > think that this is strictly a bug since it is what the database folks are > looking for. > > Bob
I did other tests with "dd bs=128k" and verified via truss that each read(2) was returning 128K. I thought I had seen excessive reads there too, but now I can't reproduce that. Creating another fs with recordsize=8k seems to make this behavior go away - things seem to be working as designed. I'll go update the (nota-)bug. -- Mike Gerdts http://mgerdts.blogspot.com/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
