Tuesday, May 24, 2005

My New Backup Strategy

Retrospect is no longer working reliably for me. Aside from the performance problems, I’m getting frequent internal assertion errors, and scheduled backups don’t always fire under Tiger.

I’ve found a combination of software that lets me do most of what I used to do with Retrospect. In some ways, it’s more convenient; in others, it’s less. It does, however, it give me more peace of mind.

My twice-daily incremental backup is now done with Synchronize! Pro X. This copies everything to an external FireWire drive, and it uses Synchronize’s archive feature to preserve old versions of the files. I compress the archive folders to save space. This is not as nice as with Retrospect, because Finder-format backups are inefficient, and the archive folders are a poor substitute for Retrospect’s snapshot feature.

To archive old versions of files and allow for off-site backups, I use CDFinder, DropDMG and Toast. I have a DropDMG configuration that creates encrypted, compressed disk images that are segmented into DVD-sized chunks, tagged with the date, and saved on the external FireWire drive. When I’m done for the day, I drag my key folders onto DropDMG, and by morning I have a bunch of .dmg and .dmgpart files.

Every few days, I burn a set of the disk images to DVD. First, I mount the disk images and drag them onto CDFinder to catalog them. Then I burn them with Toast. Overall, this works better than it did with Retrospect. By snapshotting everything to disk images before burning, I can do work (using the files that were copied to the disk images) during the burning. With Retrospect, I always dreaded starting a new DVD backup set, because it meant hours of swapping disks, and I couldn’t, for instance, run Mailsmith while backing up the Mail folder. Also, Toast is much faster at burning than Retrospect, and it fits more per DVD. A possible downside is that the DVD backups are no longer incremental, but I’ve decided that this is a plus. With each DVD set being a full backup, I can take it off-site right away.

For restores, it’s a pain to copy multiple (usually one or two) .dmgpart files back to the hard disk before I can mount the image. Restoring is rare, however, and this procedure is much faster than rebuilding a Retrospect catalog. It also works with a fresh OS installation; there's no need to locate a Retrospect install CD and download the update that lets it launch on Tiger.

Update: As of August 2005 I am now using DropDMG instead of Toast to do the burning.

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Michael, I've been using the same Sync Pro X-based backup/archival strategy for quite some time now. I use Sync Pro to maintain a bootable mirror of my startup drive (internal to the G5), and then archive files to a Firewire drive. With 120 GB on the Firewire drive, I've got (at present) about half a year of archived files. (As you probably know, Sync Pro can remove old files to maintain a specified amount of free space on the archival target drive.)

What I don't do, is create DVD-based archives -- but that sound like a good idea. What exactly to put on your DVDs -- copies of particular folders related to work? I presume you don't put a copy of your entire drive. And do you put any of the archived files on DVD?

Tobias Weber

Dunno how often I read negative stuff about Retrospect in the last weeks. If it's really that bad I will wait even longer with Tiger.
Problem is, after malicious software ate attached drives and your Mac went up in flames, how long does it take to get back to were you left off? Is an exact restore, including file dates, permissions, labels, even possible?
So far I don't see an alternative :-(

Matt, I do not put the archived files on DVD. I keep them for a while, because Sync Pro makes it easy to do that, but I don't rely on them. I think it's too much trouble (and too error-prone) to use them except to grab a particular version of a particular file, especially since they aren't package-savvy. I'd rather pull a whole folder off DVD.

As to your first question, nearly all the files that don't come from the OS DVD are in my home folder. I keep copies of the remaining ones (e.g. httpd.conf) in the home folder. I keep the home folder organized into a bunch of top-level folders, each of which is small enough to fit on a small number of DVDs: Applications, Desktop, Documents, Filing Cabinet (old and reference-type documents), Library, Mail, Mail Archive, Music, New, Pictures, Server Logs, Transient. These change at different rates, so I burn them at different rates. Transient has items, like the BBEdit Backups folder, which I don't backup at all.

Music and Pictures are a little different. I keep the contents of the Music folder arranged into DVD-sized sub-folders. Once a sub-folder fills up, I burn it and create a new folder. That way I never have to back up all the music at once. For Pictures, iPhoto doesn't give me that kind of control over the folder structure. Every few months I create a DVD set of the iPhoto library, and in between I backup new photos to CD.

Tobias, having backups on attached drives is indeed a risk. I actually have two external FireWire drives that serve the same purpose, and I never plug both of them in at the same time. Provided that I have one of these drives, an exact restore (music excepted) wouldn't take too long. If the Mac goes up in flames and takes both external drives with it, I can still get everything off DVD. That *would* take a long time. But in the disaster scenario where everything burns down, copying some DVDs would be the least of my worries.

As much as I respect the idea of regularly scheduled backups, I've always thought that running Mailsmith made them impractical -- I'd either have to quit Mailsmith before the backup started (not always possible) or assume that the user data folder was in an indeterminate state. Is your experience otherwise, or are you just more diligent than me about quitting Mailsmith on a set schedule?

I've noticed the same speed reduction in Retrospect 6.0.212, but thankfully haven't had any assertion or reliability problems.

Would you mind estimating your annual DVD media cost? I can't imagine that I'd move to a system that didn't revolve around hard disks, but I'm always interested in new data.


Nat, I agree with you about Mailsmith, hence the point I was trying to make above about how my new strategy maximizes the amount of time that I can leave Mailsmith open. Sync Pro can be set to run a script that quits Mailsmith before it starts its schedule. And I always quit it when I'm done for the day. (I have a cron job that launches it in the morning so that it can download all the new mail before I get to the computer.)

I think I'll be burning about 12 DVDs per week for this backup system. I don't really know what my average cost will be, but it's dropping. The last time I got some spindles, they were about 50 cents each for 4x. But now I see that even Amazon is selling 8x for 32 cents.

I used to use Impression, but now that Tiger's command line tools support resource forks I use a trusty old shell script to produce a compressed tar archive of my entire home directory (which fits on a single DVD) and burn that using Toast (once per day). There are no problems with accessing files during the backup. Takes about 1 hour 20 minutes to compress the archive and 12 minutes to burn and verify the DVD.

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