From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: From: erik quanstrom Date: Thu, 29 Mar 2007 08:25:27 -0400 To: 9fans@cse.psu.edu Subject: Re: [9fans] fossil+venti backup question In-Reply-To: <460BABCB.3000105@enerla.net> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Topicbox-Message-UUID: 369b218c-ead2-11e9-9d60-3106f5b1d025 On Thu Mar 29 08:07:40 EDT 2007, bituman@enerla.net wrote: > The servers gonna be on 2 UPSes on different power circuits, but ISP > staff seems to have a weird sense of humor, one time they simply pushed > the power button on one of our servers. > The place is supposed to be as safe as possible, and i'd like to have > the data on mirrored raid discs. > I am mostly worried about users deleting files etc.. > I need previous versions of files, and if the user by mistake deletes > them, then i should be able to restore them. you can get sort-of mirrored raid with fs(3). it will behave differently from a typical raid device. intraspection of the device and no degraded state. also if you have a mirror of [m0m1] and [m0] fails, then reads will work but writes will fail. typical raid mirrors would report success in both cases but the raid would be put into a degraded state. also there's no support for rebuilding the mirror if you replace a disk. you need to do that by hand. while it's a bit different than you may expect, it might be fine for you. i think you could run without venti on a mirror of cat'ed disks (fossil wants a single partition.) by setting your snap time properly and allowing snapshots to live for a relatively long time (100 days). you could even periodicly take an archive with vac onto a venti, without depending on venti for day-to-day operations. your best bet is probablly fossil+venti. - erik