Tip: Double-up the backups instead of backing up the backups.

Backups have always been a cumbersome thing for most home computer users to take the time to set up and maintain. Before Leopard, you had to install a third-party backup program and deal with proprietary formats, data structure, and compression. Apple recognized these problems with the implementation of Time Machine, and the easy "set it and forget it" method of backing up has been a great option for most home users. However, there are still times when Time Machine will not work properly. It will stop backing up certain items, give frequent errors, or have odd behavior that has the user question whether the backups are working properly.

Since errors and failure can happen in any backup system, we recommend that if you have the available resources (namely, spare external hard drives) that you set up dual, independent backups, and, in doing so, take advantage of more than one way of backing up your system. This will prevent any errors in a backup system from propagating to subsequent backups.

One strongly recommended solution that we advocate is to have both a snapshot-based system such as Time Machine in addition to a bootable clone system as well using a software package such as SuperDuper or Carbon Copy Cloner. Doing this will ensure you can both boot and access your most recently changed files in the event of either data loss or hardware failure.

Keep in mind that this is not the same as making a duplicate of your current backup. Doing that may be beneficial in the event of hardware failure, but does not protect against problems happening with your backup software and propagating through additional backups. Instead, having two systems that run separately will ensure that no problems in one backup system are carried over to the other in addition to providing a security measure in case one backup system experiences a hardware failure. External drives are cheap these days, and it pays to have a robust backup scheme that will ensure both hardware and software failures are taken into account.

It's worth noting that with multiple backups, in many instances one system may attempt to back up another one that you are trying to keep independent. For instance, Time Machine will automatically include all locally mounted volumes in its backups unless you explicitly have it ignore a specific volume (on a related side note if you're having problems with Time Machine not including some drives, check out our recent article on ensuring drives get included with your Time Machine backups). To keep backup solutions independent, be sure the drives for each backup are not included in the other one. Otherwise, in a scenario where you're set up to have a cloned drive and a Time Machine backup, the cloned drive will be again backed up to the Time Machine drive, redundantly filling it up.

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