Date: Fri, 4 Mar 2011 12:01:55 +0000 From: Dr Josef Karthauser <joe@tao.org.uk> To: Jeremy Chadwick <freebsd@jdc.parodius.com> Cc: freebsd-fs@freebsd.org Subject: Re: ZFS on a single disk? Message-ID: <9EAE56CB-0CE9-4A08-B783-3EF9B1059E62@tao.org.uk> In-Reply-To: <20110302121612.GA61020@icarus.home.lan> References: <0E00DAFC-C39F-47DC-B9AF-16419C20997F@tao.org.uk> <615F1346-E830-42E2-B229-4181B8BC56BD@exonetric.com> <53FA69D2-2EF0-4CBF-985B-6E710F15FE02@tao.org.uk> <20110302001650.GB49147@icarus.home.lan> <27423168-85BE-41B1-8E14-94F01310EFE4@tao.org.uk> <20110302121612.GA61020@icarus.home.lan>
next in thread | previous in thread | raw e-mail | index | archive | help
On 2 Mar 2011, at 12:16, Jeremy Chadwick wrote: > On Wed, Mar 02, 2011 at 10:28:50AM +0000, Dr Josef Karthauser wrote: >> >> I guess I should have been a bit clearer, I mean without any external >> devices backing them. Seeing as this is to be running on a VPS/Xen at >> a hosting environment I'm not able to add any additional devices. I'm >> not memory starved however. Is it madness to use a memory disk? (The >> instance in question will have 6gb of ram total to play with.). > > Again: don't disable the ZIL, and adjust the ARC to whatever size you > want using a combo of vm.kmem_size and vfs.zfs.arc_max. Make use of the > RAM you have available to you. :-) > Ok. That sounds like a plan. Next question, if I may. It looks like a XENHVM environment is unavailable to me, so I'm going have to stick with i386, and PAE to make the additional memory available. Given this constraint, does it still make sense to be trying to use ZFS? I had imagined that with 6GB to play with, I could dedicate 2GB of kernel space to the ZFS, leaving most of the rest for user land to play with. I've never played with PAE so I don't know whether I'm making any stupid assumptions here. Could I be, or is this still a sensible configuration to be thinking about? The grand picture is something like this then: - Hardware environment: XEN with 6GB ram, ample processor, 80GB disk. - O/S environment: FreeBSD 8.2 + PAE + XEN_PV + ZFS. - Goal: Host a number of ZFS managed jails in a secure and reliable way. Am I asking for trouble, or am I on the money? Joe p.s. there are some HVM XEN hosts out there, but it looks like they're all _much_ more expensive that the hosting provider that I'm considering, which appears to be offering a sweet spot of memory/cost.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?9EAE56CB-0CE9-4A08-B783-3EF9B1059E62>