Hello Adam, Tuesday, October 21, 2008, 2:00:46 PM, you wrote:
ANC> We're using a rather large (3.8TB) ZFS volume for our mailstores on a ANC> JMS setup. Does anybody have any tips for tuning ZFS for JMS? I'm ANC> looking for even the most obvious tips, as I am a bit of a novice. Thanks, Well, it's kind of broad topic and it depends on a specific environment. Then do not tune for the sake of tuning - try to understand your problem first. Nevertheless you should consider things like (random order): 1. RAID level - you probably will end-up with relatively small random IOs - generally avoid RAID-Z Of course it could be that RAID-Z in your environment is perfectly fine. 2. Depending on your workload and disk subsystem ZFS's slog on SSD could help to improve performance 3. Disable atime updates on zfs file system 4. Enabling compression like lzjb in theory could help - depends on how weel you data would compress and how much CPU you have left and if you are mostly IO bond 5. ZFS recordsize - probably not as in most cases when you read anything from email you will probably read entire mail anyway. Nevertheless could be easily checked with dtrace. 6. IIRC JMS keeps an index/db file per mailbox - so just maybe L2ARC on large SSD would help assuming it would nicely cache these files - would need to be simulated/tested 7. Disabling vdev pre-fetching in ZFS could help - see ZFS Evile tuning guide Except for #3 and maybe #7 first identify what is your problem and what are you trying to fix. -- Best regards, Robert Milkowski mailto:[EMAIL PROTECTED] http://milek.blogspot.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
