What good is backup software that can't perform a restore? That's what I've been wondering in the week since the main hard drive in my PowerMac G5 died. Having lost another drive earlier in the year for which I had no backup, I'd finally setup a proper backup system, using external SATA drives as the destinations, and Apple's Backup version 3.1 (a part of the ".Mac" package) to perform nightly incremental backups. So, my latest drive failure seemed like one failure too many for the year, but one for which I was prepared. Or so I thought until I tried to restore my files. Then I found that Backup 3.1 would only restore a certain number of the files early in the backup set before it would crash. Any attempt to restore other files from the set resulted only in a crash. Specifically, Backup would proceed to very slowly consume about 2.1 GB of virtual memory, and then it would crash, writing the following to "backup.log":
Backup(1104,0x1ace800) malloc: *** vm_allocate(size=1069056) failed (error code=3) Backup(1104,0x1ace800) malloc: *** error: can't allocate region Backup(1104,0x1ace800) malloc: *** set a breakpoint in szone_error to debug
As best I can tell, this means that between the 2.1 GB of virtual memory it used-up (as observed in Activity Monitor), it also consumed a further 1.9 GB of combined real, private and shared memory, and then died because its 32-bit address space was exhausted. Brilliant. Thank you so much, Apple, for backup software that can backup, but not restore. That's innovative, alright, but not in a good way.
Needless to say, I submitted many crash reports, and a proper bug report, complete with a plea for help, but none has been offered in the following week.
I have, however, salvaged a fair number of files by manually mounting the ".sparseimage" files hidden inside the backup "files", but with seventy incrementals since the last full backup, sifting through everything by hand is a major problem. And files with resource forks, along with executables, can't be salvaged that way at all. Oh, thank you, Apple.
So, based on this experience, let me warn anyone else out there who's using Apple's Backup program: Don't. If your backup sets are small, it may well work for you, but once they grow large enough, you'll reach the same point I did, where it'll crash rather than restore your files. And you won't know that you've reached that point until it's too late.
As an aside, the drive that died (a 250 GB Maxtor that Apple sold me with the G5) had a controller that supports SMART (Self-Monitoring, Analysis and Reporting Technology), and I had installed the DiskWarrior extension that routinely checks the SMART status of the mounted drives and is supposed to display an alert when a drive reports that it is beginning to fail. No such warning appeared. This is the second SMART-equipped mechanism that I've lost (but the first since installing the DiskWarrior extension), and I haven't seen SMART do a thing. Has anyone out there actually seen SMART do its stuff?
The one thing that did work well in this mess was the backup scheme ("vaults") that Apple's Aperture team integrated into that application. There was no problem restoring from the vault I'd created on one of my backup drives, and because support for vaults is well integrated into Aperture, I'd (1) actually setup a vault (the splash screen gently nags you to do so), and (2) kept it current. If any members of the Aperture team happen to read this, let me just say: Thank you. And please go beat the metaphorical crap out of whoever's responsible for the Backup application; they make everybody else at Apple look bad.