Tuesday, December 16, 2008

Restoring my iMac via Time Machine...

So my iMac has been a tad flaky lately. It's not something I can easily pinpoint. Something just isn't right. More occurrences of the the spinning rainbow wheel, simple actions causing the finder not to respond, stuff like that.   The kind of stuff that makes pseudo technical people say thinks like "it must be spyware" or "after a while when you get too many files the machine bogs down" or "the machines old". My favorite is the windows standard refrain "Defragment your C-drive" which can be valid, but more often than not isn't the real problem. I thought I was on to something when I noticed an app that would go in and out of "not responding" in activity monitor, but that turned into a dead end. So I decided to look at my disk utilization and my drive was fairly fragmented. More importantly, I had data from the top to the bottom of the drive. It would have been interesting to see if the pagefile was split between two far flung tracks. So I decided to run Drive Genius and defragment the drive overnight tonight. I boot up the DVD and it proceeds to do a health check and reports an error (which I don't have in front of me right now). Interestingly Disk Utility reported no such error when booted from the disk. But for what ever reason, this drive had something wrong with the filesystem. No problem, I have recent time machine backups, I'll just reformat and restore.


Oh, if it was that simple for me. So it turns out that my version of iMac (came installed with 10.4) the Leopard (10.5) DVD, a blank internal disk drive, and a valid time machine backup isn't very simple to restore. The mistake I made was going into disk manager and erasing "Macintosh HD" since Time Machine was going to do it anyway. But if the drive had died and I put a new one in to replace it, I would have hit this issue too it seems. For reasons that aren't clear yet (AKA google didn't have an answer on the first page of hits) Time Machine won't restore to an unformatted drive, even though it formats the drive during the restore (I come to find out later). Had I known it was going to reformat the drive on it's own I wouldn't have done it myself. Anyway, I had to install 10.5 on the drive first (45 minutes), then reboot, reboot the DVD again and then do a restore. 4 hours later, my 120Gb of data is back on the internal drive.


Then the rest of the fun. So Time Machine backs up every file that changes except for files that the OS can rebuild on it's own, like app caches and stuff. If you download a lot of crap, like linux ISO files and other large files off the net, (especially if they have .RAR and .PAR2 files) you will quickly fill your time machine drive with unnecessary junk. Virtual machine drives are a another great example of this extra backups. They change all the time. When I ran one of my VM's all day, I had 8 hourly backups of a 15Gb file. Yikes! The solution is to add exclusions to your time machine config via the "Options" page of the preference pane. Then you handle backups of the troublesome directories manually. Which is great until you forget to handle them manually right before you reformat your drive. DOH! Fortunately it's not something I can't download again, but on the other hand, it was a lot of bandwidth used. Then again, since I probably couldn't tell you what was in those two temp folders, it's probably a good indicator I didn't really need them.


Anyway, the restore is done and looks like I'm back in operation. My return to service time 4 hours 11 minutes. On the plus side the dishwasher is loaded, the counters wiped down, laundry folded and ironed.



Listened to: Why Can't I Fall In Love from the album "Pump Up The Volume Original Soundtrack" by Ivan Neville

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