Don't want to give conflicting advice, and would suggest you certainly try the 30 sec thing first. I'm already on 10 myself but haven't pushed further.
In my own case I've not had any issue with zfs in particular since I applied the ZFS zil/prefetch disable loader.conf tunables 10 hours ago. I am observing this now. For the record .. What ata chipset/motherboard and model of disk have you got ? Have you seen any smart errors (real or otherwise) ? What do your 'zpool status' counters look like ? -- Alex On Tue, 2008-07-15 at 12:55 -0700, Matthew Dillon wrote: > :Went from 10->15, and it took quite a bit longer into the backup before > :the problem cropped back up. > > Try 30 or longer. See if you can make the problem go away entirely. > then fall back to 5 and see if the problem resumes at its earlier > pace. > > -- > > It could be temperature related. The drives are being exercised > a lot, they could very well be overheating. To find out add more > airflow (a big house fan would do the trick). > > -- > > It could be that errors are accumulating on the drives, but it seems > unlikely that four drives would exhibit the same problem. > > -- > > Also make sure the power supply can handle four drives. Most power > supplies that come with consumer boxes can't under full load if you > also have a mid or high-end graphics card installed. Power supplies > that come with OEM slap-together enclosures are not usually much better. > > Specifically, look at the +5V and +12V amperage maximums on the power > supply, then check the disk labels to see what they draw, then > multiply by 2. e.g. if your power supply can do [EMAIL PROTECTED] and > you have > four drives each taking [EMAIL PROTECTED] (and typically ~half that at > 5V), thats > 4x2x2 = [EMAIL PROTECTED] and you would probably be ok. > > To test, remove two of the four drives, reformat the ZFS to use just 2, > and see if the problem reoccurs with just two drives. > > -Matt > > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "[EMAIL PROTECTED]"
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