On Fri, 10 Jun 2011, Jeremy Chadwick wrote:
We tried using dedup on one of our systems, but within 10-15 minutes turned it off. I believe the added CPU overhead of dedup was causing the system to act "bursty" in other non-ZFS-related tasks; e.g. turn on dedup, then in a SSH window hold down the letter "q" indefinitely, then in another window do some ZFS I/O. The "q" would stall for 1-2 seconds at times (SSH connectivity was via direct private LAN, so network latency was not what we seen). Without dedup this behaviour wasn't seen at all. I'm happy to try any advice/patches on a locally-accessible box (e.g. private LAN, VGA console is right behind me, etc.).
Dedup can require a huge amount of RAM, or a dedicated L2ARC SSD, depending on the size of your storage. You should not enable it unless you are prepared for the consequences.
Solaris 11 Express does not admit to supporting dedup even though it can be enabled in previous OpenSolaris and is supported in Oracle's NAS products (which run a variant of Solaris 11).
Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
