Date: Tue, 16 Feb 2010 10:56:51 -0500 From: "Peter C. Lai" <peter@simons-rock.edu> To: Artem Belevich <fbsdlist@src.cx> Cc: Alexander Leidinger <alexander@leidinger.net>, freebsd-stable@freebsd.org, Jeremy Chadwick <freebsd@jdc.parodius.com> Subject: Re: hardware for home use large storage Message-ID: <20100216155651.GI4648@cesium.hyperfine.info> In-Reply-To: <ed91d4a81002151425ib665187g68a5b13aa4ee4eb9@mail.gmail.com> References: <cf9b1ee01002150049o43fced71ucb5776a0a1eaf4cf@mail.gmail.com> <20100215090756.GA54764@icarus.home.lan> <20100215105000.101326yj01j0f64g@webmail.leidinger.net> <20100215122744.GA57382@icarus.home.lan> <20100215161105.14071eiflhc9le68@webmail.leidinger.net> <ed91d4a81002150854w421b054oc81eb88ae767f5b4@mail.gmail.com> <1140.69.37.94.221.1266256820.squirrel@lock.simons-rock.edu> <ed91d4a81002151425ib665187g68a5b13aa4ee4eb9@mail.gmail.com>
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On 2010-02-15 02:25:57PM -0800, Artem Belevich wrote: > > How much ram are you running with? > > 8GB on amd64. kmem_size=16G, zfs.arc_max=6G > > > In a latest test with 8.0-R on i386 with 2GB of ram, an install to a ZFS > > root *will* panic the kernel with kmem_size too small with default > > settings. Even dropping down to Cy Schubert's uber-small config will panic > > the kernel (vm.kmem_size_max = 330M, vfs.zfs.arc_size = 40M, > > vfs.zfs.vdev.cache_size = 5M); the system is currently stable using DIST > > kernel, vm.kmem_size/max = 512M, arc_size = 40M and vdev.cache_size = 5M. > > On i386 you don't really have much wiggle room. Your address space is > 32-bit and, to make things more interesting, it's split between > user-land and kernel. You can keep bumping KVA_PAGES only so far and > that's what limits your vm.kmem_size_max which is the upper limit for > vm.kmem_size. > > The bottom line -- if you're planning to use ZFS, do switch to amd64. > Even with only 2GB of physical RAM available, your box will behave > better. At the very least it will be possible to avoid the panics > caused by kmem exhaustion. > > --Artem Well this ZFS box (which admittedly is mostly a testbed) is only a lowly NetBurst Gallatin Xeon, pre-amd64 :( -- =========================================================== Peter C. Lai | Bard College at Simon's Rock Systems Administrator | 84 Alford Rd. Information Technology Svcs. | Gt. Barrington, MA 01230 USA peter AT simons-rock.edu | (413) 528-7428 ===========================================================
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