From owner-freebsd-questions@FreeBSD.ORG Thu Oct 9 23:17:09 2014 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id BBB39951 for ; Thu, 9 Oct 2014 23:17:09 +0000 (UTC) Received: from cosmo.uchicago.edu (cosmo.uchicago.edu [128.135.52.97]) by mx1.freebsd.org (Postfix) with ESMTP id 943D5B7C for ; Thu, 9 Oct 2014 23:17:09 +0000 (UTC) Received: by cosmo.uchicago.edu (Postfix, from userid 48) id B76ECCB8CB1; Thu, 9 Oct 2014 18:17:02 -0500 (CDT) Received: from 76.192.184.214 (SquirrelMail authenticated user valeri) by cosmo.uchicago.edu with HTTP; Thu, 9 Oct 2014 18:17:02 -0500 (CDT) Message-ID: <56695.76.192.184.214.1412896622.squirrel@cosmo.uchicago.edu> In-Reply-To: References: <1412732931033.813626ca@Nodemailer> Date: Thu, 9 Oct 2014 18:17:02 -0500 (CDT) Subject: Re: Next Steps to Debug ZFS Hang? From: "Valeri Galtsev" To: "FreeBSD Questions" Reply-To: galtsev@kicp.uchicago.edu User-Agent: SquirrelMail/1.4.8-5.el5.centos.7 MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 09 Oct 2014 23:17:09 -0000 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 ++++++++++++++++++++++++++++++++++++++++