11:58 am, 11 Feb 06
disk recovery, end
(Since this will be the last post on the subject, here's the brief recap: I had all my data on a mirrored RAID and then both disks failed within a few weeks of each other. My fault, stupid planning, etc. but it had pretty much everything that mattered to me. Here we are, a year later:)
I mailed
caladri about libufs ('cause her name's on it) and she made the (in retrospect) obvious observation that I really should just try mounting the image in FreeBSD. So after a few failed attempts with different boot CDs, I found FreeSBIE, a FreeBSD live CD that includes gvinum. Then I mounted the image (
As far as I can tell, almost everything's back, hooray! It's been a year since I've seen this data, and I had pretty much thought it was gone for good.
This fiasco made me realize I was going about data protection the wrong way. It goes back to threat models, sorta: what was I trying to protect against? Mirrored RAID protects against disk failure in a high-availability sort of way, but e.g. a power supply hiccup or bad controller (or even user error) and the data's gone anyway. Much better is a real backup strategy, and though it's not nearly as fun as dorking around with vinum/LVM/etc. it can be done with comparable cost and effort.
And finally, the whole situation drives home a point that's been a recurring theme in my life: there's all this junk (memories, data, things) that seems like it'd be awful if you lost it, but really, it's not so bad. Ultimately it's just stuff, and all of the interesting bits are in my head.
I mailed
caladri about libufs ('cause her name's on it) and she made the (in retrospect) obvious observation that I really should just try mounting the image in FreeBSD. So after a few failed attempts with different boot CDs, I found FreeSBIE, a FreeBSD live CD that includes gvinum. Then I mounted the image (man mdconfig), let gvinum recognize it, and ran an fsck on /dev/gvinum/raid. (I hadn't run an fsck back when the disk started going bad because you don't want to cause a bunch of writes on a failing disk...)As far as I can tell, almost everything's back, hooray! It's been a year since I've seen this data, and I had pretty much thought it was gone for good.
This fiasco made me realize I was going about data protection the wrong way. It goes back to threat models, sorta: what was I trying to protect against? Mirrored RAID protects against disk failure in a high-availability sort of way, but e.g. a power supply hiccup or bad controller (or even user error) and the data's gone anyway. Much better is a real backup strategy, and though it's not nearly as fun as dorking around with vinum/LVM/etc. it can be done with comparable cost and effort.
And finally, the whole situation drives home a point that's been a recurring theme in my life: there's all this junk (memories, data, things) that seems like it'd be awful if you lost it, but really, it's not so bad. Ultimately it's just stuff, and all of the interesting bits are in my head.
And now a backup?
Now you've recovered this data, you are going to make a backup of it, right? Today? For a lot of the things you mention that you don't want to lose, even writing it out to CD-R (or DVD[+-]R) a couple of times a year does a whole lot to minimise the "OMG I just lost my life" factor.A large remote disk and/or a external disk tray (firewire, USB2, etc) and rsync run regularly makes for a more convenient backup for a lot of stuff, but there's still a risk of accidentally deleting things that you don't have with a "permanent" media like CD-R/DVD[+-]R. (Permanent in the sense that there's no "rm -r" option, just throwing it out and starting again, or physical destruction.)
I'm glad you got your data back though.
Ewen
PS: If you lose a drive in RAID-1 you need to replace it fairly quickly. I had a two drive RAID-1 lose drives a few weeks apart. Fortunately by the time the second one went, I'd had a replacement first drive in for a few weeks.
Re: And now a backup?
Yes, backups are now planned. :)I've considered DVD but I don't think they store enough. The disk's at 109gb right now, which is a lot of DVDs. Though I guess all of my pictures are under a gig, so that'd be a good candidate...
Re: And now a backup?
Yes, that's pretty much what I meant. Back up the things you _really_ don't want to lose onto CD-R or DVD[+-]R. As you say it's not that suitable for backing up an entire drive (although back in the days of floppy backups I did much worse -- 30+ floppy backup sets), but you can at least pick out the really critical things.If your drive is anything like mine there's a lot of stuff which can be retrieved simply by Googling for where you downloaded it and downloading it again. And there's much less need to back that up regularly. (In fact most of that I exclude from even my tape backups).
And seriously I'd really suggest spending an hour or two _today_ writing DVDs of the stuff that is most important to you. And maybe storing it off-site as well (eg, friends, parents, whatever).
Ewen
Re: And now a backup?
Two drives failing within weeks of each other seems to be pretty common, especially since people usually purchase 2 x the same drive at the same time.Reading your story gives me a bit of motivation to go set that up :)
backup strategy
RAID is worthless in desktop machines. Completely without merit in that situation.Removable media is also worthless. If a tape or disc goes bad while sitting on a shelf -- and they do -- you'll only know about it years later when you try to restore.
Assuming you have two physically distinct personal computers, put the same amount of disk in both of them, twice as much as you need, and rsync between them once a week or so. If one drive dies, you've got a complete copy on the other machine, and you know about the problem right away, because you're actually using both disks. (The other nice thing about this method is that the two machines don't even have to be the same OS.)
Then have a third drive of the same size in an external USB2 or FW enclosure. Back up to that every six months to a year and keep it elsewhere, like in your desk at work.