Date: Sat, 11 Sep 2010 03:05:58 -0400 From: jhell <jhell@DataIX.net> To: Pawel Jakub Dawidek <pjd@freebsd.org> Cc: freebsd-fs@freebsd.org Subject: Re: Swap on ZFS Volume still panics? Message-ID: <4C8B2A56.8080809@DataIX.net> In-Reply-To: <20100910073912.GC2007@garage.freebsd.pl> References: <AANLkTin4DAY%2BWXOpckWJCs437BGg0mjAFzRv%2BiDEG-F1@mail.gmail.com> <20100910073912.GC2007@garage.freebsd.pl>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 09/10/2010 03:39, Pawel Jakub Dawidek wrote: > On Wed, Sep 08, 2010 at 07:19:40PM +0300, App Deb wrote: >> Reading the wiki guides they mention the official way to add swap volumes on >> ZFS (set org.freebsd:swap=on etc..), >> >> So I thought that it should work now, But I just got a panic in 8.1-RELEASE >> after a heavy memory situation that touched swap for the first time. > > Swap on ZVOL is still not recommended. Where did you find information > that it now recommended? I can't find anything about swap on > http://wiki.freebsd.org/ZFS and on > http://wiki.freebsd.org/ZFSQuickStartGuide there is a note that it is > not recommended. Let me know where it is advised and I'll remove it or > add a note (if the documentation is mine). > >> It is a hassle to add gmirror volumes for swap on full zfs systems, is there >> any workaround for this, or any news when a fix is coming or if it is >> coming? > > I've no plans to fix it, maybe with ZFSv28 it will be easier to fix, but > this is really low priority. If you use full ZFS system the recommended > layout is described here: > > http://blogs.freebsdish.org/pjd/2010/08/06/from-sysinstall-to-zfs-only-configuration/ > >> If the current code procudes guaranteed panics with zfs swap, I think that >> every mention of swap on zfs should be removed from the semi-official wiki >> guides. > > BTW. If this issue will be worked on in the future, it will be useful to > actually see your panic, backtrace and other debug info. To be honest, I > didn't expect it to panic, rather deadlock. Maybe panic is from deadlock > resolver? Hard to say without any debug info. > For reference I have been using swap on ZFS for a while. I recieve no panics when doing so and have the following properties set. exports/swap refreservation 2G local exports/swap primarycache none local exports/swap secondarycache none local exports/swap org.freebsd:swap on local As someone already mentioned, it might help to also change volblocksize property to 4k but I have never had to do that as changing the primary and secondary caches were enough to keep it from panic here. I would be interested to hear if this helped anyone else. Regards, - -- jhell,v -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (FreeBSD) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJMiypWAAoJEJBXh4mJ2FR+OeYH/0jxC6aJlOHVKxL8UCeA+94s V3scx8jDH3ZiqoCno4FLgkzW41E1NUGlvZA4arLe76Fv2/QeU53ZyZD160WcRYax fhOyUQeHPJ2QecSnsmBJS2aJSvl9abdNYMyEhA1YxoApvBRcm7FEvAt3qY8Dj5uQ jJPN4zOxM6CGq6FUWEbAmmtpIKSi/TLNZqvpxN1GcJeyfyFJroswiEisWYq2rkEA MqXEe13DqVdjS0yysyMHsGNqfgpByDRQJ4M/nnGMPHyUlGdItFJR2B3htzVdeb88 69TnEw5rwiztNm/629jyBaDdynjwortP3Jw37Mij6SE/kHS/+kZ6dfCb7eZHPmA= =PAEM -----END PGP SIGNATURE-----
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