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On Wed, 21 Oct 2009 10:00:50 +0100 Rob Beard wrote: > Grant Sewell wrote: > > On Tue, 20 Oct 2009 13:18:41 +0100 (BST) > > ste@xxxxxxxxxxxxxxxxx wrote: > > > > > >>> 2 USB drives where periodically rsync is run to duplicate drive 1 > >>> onto drive 2. Drive 1 is static, drive 2 (should) get removed > >>> every evening and taken off-site. > >>> > >>> If the two drives were setup in a software-based RAID-1 (mirror) > >>> configuration, would they automatically reconcile any differences > >>> when drive 2 was re-attached? If not, how can differences between > >>> two software RAID-0 drives be reconciled? Is there a command that > >>> initiate the reconciliation? Can this be added to a udev rule so > >>> that when drive 2 is re-attached the reconciliation happens > >>> automatically? > >>> > >> --snip-- > >> > >> Interesting. I guess you could do that, but I'm not sure why you'd > >> want to. Why are you taking the redundant disk off site? This > >> smells a bit like the old backup vs redundancy confusion. Any way, > >> maybe LVM snapshots are what you really want? They'll let you > >> capture a whole, consistent filesystem image while it's still in > >> use. > >> > >> Steve. > >> > > > > What's going on is this - we have a Windows SBS 2008 virtual machine > > running inside VMWare ESXi. VMWare ESXi is an interesting product > > but lacks the ability to show physically attached USB drives to any > > of the guest OSes. The original plan was for SBS 2008 to backup to > > the USB drives in-turn, so Monday would be on Disk 1, Tuesday on > > Disk 2, Wednesday on Disk 1, etc, etc. Installing SBS 2008 inside > > VMWare ESXi, however, put the kybosh on that plan. > > > > So now we have the SBS 2008 machine performing regular backups over > > the network to my machine which is setup to share USB Disk 1 with > > SAMBA. Since the only things that was mandatory was that one of the > > disks be taken off-site every night, I decided that Disk 1 should > > be the primary backup drive and Disk 2 should be a duplicate of it > > that can be taken off-site every night. > > > > I have already made it simple for whoever takes the drive home > > (usually me, but if I'm not in...) by putting an oversized icon on > > my desktop with "REMOVE BACKUP DRIVE" as the title - this points to > > a quick script that will establish if anything is currently using > > the "take home" drive and if not, unmount it and informs the user > > to turn off and disconnect the drive. > > > > There is a cron job that rsyncs the two drives together, but that > > can take a very long time (SBS 2008 backup dumps everything as a > > VHD file - so our backup is 1 file at 78GB with numerous small XML > > files surrounding it). > > > > What I was hoping was to have a smoother system where the two drives > > are essentially identical at the point where the "take home" drive > > gets removed, and can automatically reconcile the differences > > between the two when it gets reconnected. > > > > It's not a big issue as our current system does work, and we will be > > reviewing our backup procedures soon anyway. > > > > Cheers. > > Grant. :) > > > > > Not using ESXi server this is a bit of a long shot, but I wonder if > this might work? (of course it'll require a bit of tweaking to take > Windows out of the equation). > > Rob The software-RAIDed USB drives would not be connected to the ESXi machine. They'd be connected to my Debian workstation and Windows would "backup" over the network to an SMB share - that share points to a directory on the filesystem on the RAID. Grant. -- The Mailing List for the Devon & Cornwall LUG http://mailman.dclug.org.uk/listinfo/list FAQ: http://www.dcglug.org.uk/linux_adm/list-faq.html