Date: Thu, 9 Oct 2014 18:17:02 -0500 (CDT) From: "Valeri Galtsev" <galtsev@kicp.uchicago.edu> To: "FreeBSD Questions" <freebsd-questions@freebsd.org> Subject: Re: Next Steps to Debug ZFS Hang? Message-ID: <56695.76.192.184.214.1412896622.squirrel@cosmo.uchicago.edu> In-Reply-To: <D06BCA779173763DDF3CD614@[192.168.1.50]> References: <1412732931033.813626ca@Nodemailer> <DAA5D9129F9D691C69C7A2EF@192.168.1.50> <CAM72HBZvpXSeVMjQvWGiKhqeosMzxDBr9zAFJ8h7QByfhd7%2BUQ@mail.gmail.com> <D06BCA779173763DDF3CD614@[192.168.1.50]>
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On Thu, October 9, 2014 5:53 pm, Daniel Staal wrote: > --As of October 8, 2014 9:28:05 PM -0700, Nick Sivo is alleged to have > said: > >>> Not sure if this will be helpful, but at least it shouldn't hurt: When >>> was the last time you ran a scrub? Also, how much RAM do you have and >>> where is your swap? (The only times I've had permanent hangs from ZFS >>> was when I ran out of RAM and was trying to swap to ZFS...) >> >> The server has 64GB ECC RAM, and no swap at the moment. I've since >> rebooted the box, but a scrub today revealed no errors, and there was >> nothing in the console or any log files about disk or controller >> errors or timeouts. > > --As for the rest, it is mine. > > Note that I'm still just going by 'standard checks', but why don't you > have > any swap? I know you probably wouldn't use it with that much RAM around, > but FreeBSD still performs better with it - and it wouldn't surprise me > completely if that was causing your issue. I'm petrified. Is that so? I mean, as I understood you, 64 GB RAM machine running under FreeBSD (say, 9.3) still needs some amount of SWAP for better performance, right? Valeri > (It shouldn't, in an ideal > world - but it's an oddity on your system that might be causing issues, if > there's an uncovered corner case.) > > Setting up a small ramdisk for swap - or even putting some small > swap-on-zfs - might be worth checking to see if it seems to prevent the > issue. (Note that swap-on-zfs has a 'worst case' scenario that crashes > the > box if you run out of RAM. It's happened to me, and I was able to > recover, > but it took a while.) > > Anyway, I'm mostly trying to keep your question alive in hopes that > someone > who's more knowledgeable can answer it. ;) > > Daniel T. Staal > > --------------------------------------------------------------- > This email copyright the author. Unless otherwise noted, you > are expressly allowed to retransmit, quote, or otherwise use > the contents for non-commercial purposes. This copyright will > expire 5 years after the author's death, or in 30 years, > whichever is longer, unless such a period is in excess of > local copyright law. > --------------------------------------------------------------- > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to > "freebsd-questions-unsubscribe@freebsd.org" > ++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++
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