Date: Sun, 6 Jan 2008 17:05:44 +0100 From: Maciej Suszko <maciej@suszko.eu> To: freebsd-current@freebsd.org Subject: Re: When will ZFS become stable? Message-ID: <20080106170544.93f7ab1b.maciej@suszko.eu> In-Reply-To: <4780F7C0.5010101@FreeBSD.org> References: <fll63b$j1c$1@ger.gmane.org> <20080104163352.GA42835@lor.one-eyed-alien.net> <9bbcef730801040958t36e48c9fjd0fbfabd49b08b97@mail.gmail.com> <200801061051.26817.peter.schuller@infidyne.com> <9bbcef730801060458k4bc9f2d6uc3f097d70e087b68@mail.gmail.com> <4780D289.7020509@FreeBSD.org> <20080106144627.a91a62c1.maciej@suszko.eu> <4780F7C0.5010101@FreeBSD.org>
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Kris Kennaway wrote: > Maciej Suszko wrote: > > Kris Kennaway wrote: > >> Ivan Voras wrote: > >>> On 06/01/2008, Peter Schuller <peter.schuller@infidyne.com> wrote: > >>>>> This number is not so large. It seems to be easily crashed by > >>>>> rsync, for example (speaking from my own experience, and also > >>>>> some of my colleagues). > >>>> I can definitely say this is not *generally* true, as I do a lot > >>>> of rsyncing/rdiff-backup:ing and similar stuff (with many files / > >>>> large files) on ZFS without any stability issues. Problems for me > >>>> have been limited to 32bit and the memory exhaustion issue rather > >>>> than "hard" issues. > >>> It's not generally true since kmem problems with rsync are often > >>> hard to repeat - I have them on one machine, but not on another, > >>> similar machine. This nonrepeatability is also a part of the > >>> problem. > >>> > >>>> But perhaps that's all you are referring to. > >>> Mostly. I did have a ZFS crash with rsync that wasn't kmem > >>> related, but only once. > >> kmem problems are just tuning. They are not indicative of > >> stability problems in ZFS. Please report any further non-kmem > >> panics you experience. > > > > I agree that ZFS is pretty stable itself. I use 32bit machine with > > 2gigs od RAM and all hang cases are kmem related, but the fact is > > that I haven't found any way of tuning to stop it crashing. When I > > do some rsyncing, especially beetwen different pools - it hangs or > > reboots - mostly on bigger files (i.e. rsyncing ports tree with > > distfiles). At the moment I patched the kernel with > > vm_kern.c.2.patch and it just stopped crashing, but from time to > > time the machine looks like beeing freezed for a second or two, > > after that it works normally. Have you got any similar experience? > > That is expected. That patch makes the system do more work to try > and reclaim memory when it would previously have panicked from lack > of memory. However, the same advice applies as to Ivan: you should > try and tune the memory parameters better to avoid this last-ditch > sitation. As Ivan said - tuning kmem_size only delay the moment system crash, earlier or after it happens - that's my point of view. > P.S. It sounds like you do not have sufficient debugging configured > either: crashes should produce either a DDB prompt or a coredump so > they can be studied and understood. You're right - I turned debugging off, because it's not a production machine and I can afford such behaviour. Right now, using kernel with kmem patch applied it's ,,usable''. -- regards, Maciej Suszko.
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