Where did my back­ups go?

Mac Format - - APPLE TALK -

I’m us­ing Time Ma­chine to back up to a Time Cap­sule. Last week a mes­sage popped up say­ing “Time Ma­chine com­pleted a verification of your back­ups on Time Cap­sule. To im­prove re­li­a­bil­ity, Time Ma­chine must cre­ate a new backup for you. New backup will re­move ex­ist­ing backup his­tory. This could take sev­eral hours”.

I’m some­what re­luc­tant for my ex­ist­ing his­tory to be re­moved un­til I’m sure what has hap­pened. I tried Disk Util­ity on the Time Cap­sule and it said the Time Ma­chine back­ups were cor­rupt! What could pos­si­bly have caused this? June O’Ke­effe

Your Time Cap­sule backs up onto a hard disk, and this disk is just as vul­ner­a­ble to er­rors as the one in your Mac. The idea be­hind back­ing up is sim­ply that it’s very un­likely both disks will fail at the same time. If your Mac disk fails first, you re­store it from the backup. If the Time Cap­sule fails, then you recre­ate the backup from the files on your Mac. It’s true that you’ll lose the en­tire his­tory of file changes in your Time Ma­chine backup, but it’s bet­ter to have a sin­gle backup snap­shot that works than many cor­rupted snapshots.

If the his­tory of your files is im­por­tant to you, then you shouldn’t rely on Time Ma­chine to pre­serve it. At that point the data on your Time Cap­sule stops be­ing a backup and be­comes unique data that it­self needs to be backed up!

Time Ma­chine rou­tinely ver­i­fies its own data­base struc­ture to make sure you can trust your backup, and when it flags up a prob­lem the best thing to do is recre­ate your backup im­me­di­ately. If the thought of be­ing tem­po­rar­ily with­out a backup makes you queasy, I sug­gest you do as I do and keep two backup sets. Let Time Ma­chine back up, ev­ery hour, just the files that have changed, and also use a sep­a­rate drive to pe­ri­od­i­cally make a sec­ond copy of your Mac’s disk us­ing soft­ware such as Su­per Duper (about £20, shirt­pocket.com).

Back­ups are just files and they can get dam­aged or lost just like the orig­i­nal copies. Learn more about Time Ma­chine and cloud back­ups on page 28.

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