On Mon, 13 Jul 2009, Ross Walker wrote:
Have you tried limiting the ARC so it doesn't squash the page cache?
Yes, the ARC is limited to 10GB, leaving another 10GB for the OS and applications. Resource limits are not the problem. There is a ton of memory and CPU to go around.
Current /etc/system tunables: set maxphys = 0x20000 set zfs:zfs_arc_max = 0x280000000 set zfs:zfs_write_limit_override = 0xea600000 set zfs:zfs_vdev_max_pending = 5
Make sure page cache has enough for mmap plus buffers for bouncing between it and the ARC. I would say 1GB minimum, 2 to be safe.
In this testing mmap is not being used (cpio does not use mmap) so the page cache is not an issue. It does become an issue for 'cp -r' though where we see the I/O be substantially (and essentially permanently) reduced even more for impacted files until the filesystem is unmounted.
Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, 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
