Date: Mon, 13 Sep 2010 00:14:14 +0300 From: App Deb <appdebgr@gmail.com> To: jhell <jhell@dataix.net> Cc: freebsd-fs@freebsd.org, Pawel Jakub Dawidek <pjd@freebsd.org> Subject: Re: Swap on ZFS Volume still panics? Message-ID: <AANLkTi=K=KGTW5spj6qcpjv3qjV%2BDsR4BVw4Wd%2BFq%2Bbt@mail.gmail.com> In-Reply-To: <4C8B2A56.8080809@DataIX.net> References: <AANLkTin4DAY%2BWXOpckWJCs437BGg0mjAFzRv%2BiDEG-F1@mail.gmail.com> <20100910073912.GC2007@garage.freebsd.pl> <4C8B2A56.8080809@DataIX.net>
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I just tried your settings (setting primary and secondary cache to none). (also tried it with checksum=off and volblocksize=4k, all together) It somewhat helped. In the beginning I though it would deadlock. The system was inaccessible for ~10 minutes, but after that it managed to allocate the required swap, and the system resumed. I measured the speed that it allocated swap and it was only around ~0.4MB/s max. With the native freebsd-swap partition the speed using my "selfmade memory filling program" it almost reaches native disk speeds (~80MB/s). I still see a problem here. Thanks. On Sat, Sep 11, 2010 at 10:05 AM, jhell <jhell@dataix.net> wrote: > -----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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