Let’s face it, it’s really not about your computer. It’s about your files! Your email, your pictures, your documents, your music, your movies…those are what’s really important. If you have a proper backup, even if your computer is lost, stolen, destroyed, or self-destructs, your data is safe if you have a backup. For that reason, everyone should back up their computer

Kinds of backups

Mirror backups initially back up your entire internal drive, and subsequent backups copy whatever is necessary to make the backup identical to the internal drive at the time of the backup.

If you have added or modified files on your computer, the new files or later versions of files will be copied to the backup, replacing earlier versions. If you’ve trashed files or folders on the computer, they will be deleted from the backup.

The upside of a mirror backup is that it’s bootable and identical to the drive in your computer as of the last backup. If your internal drive fails, you can boot up your computer, or any other computer from your backup, and lose nothing except whatever work you’ve done since the last backup.

The downside (or limitation) of a mirror backup is that if need to recover a file you deleted a day, week, or month ago, there is no way to recover it…if it was deleted from your computer, it was deleted from the backup too.

Archival backups also initially back up your entire internal drive. Subsequent backups copy whatever has changed since the previous backup…without deleting the older or deleted files.

The upside of an archival backup is that you can recover files or folders you trashed.

The downside of an archival backup is that its not bootable…if the drive in your computer fails, you’d have to do a complete restore before you can boot up, which takes time.

Backup Software

Time Machine, which is built into all versions of MacOS since 10.5, is excellent archival backup software. There is nothing to buy…it initially backs up your entire computer, and then updates the backup hourly as long as the backup drive is connected. It literally runs itself on auto-pilot.

For mirror backups, you must use third party software. Our favorite is Carbon Copy Cloner (another popular choice is called SuperDuper!). Not only with either backup up your internal drive, you can set them to do recurring backups…daily, multiple times a day, weekly, monthly…whatever works for you.

Backup Locations

An external drive is the most common place for your backup. The drive directly connects to your computer by USB, Thunderbolt, or for earlier Macs, FireWire, and they can be used for either mirror or archival backups. If you’re going to use an external drive for a mirror backup, it’s capacity must at least match the capacity of the drive being backed up. If you’re using the drive for an archival backup, the drive should be at least twice the size of the drive being backed up…to leave room for the deleted and older versions of files to remain even when they’ve been trashed on the internal drive.

The upside of using an external drive is that it remains in your possession all the time.

The downside is that if you keep the backup drive where the computer is, and there is a catastrophe like a fire, flood, or theft, the backup drive will be damaged or lost just like the computer.

A cloud server. There are companies that specialize in providing space on their servers to which you can backup your entire computer…via the internet. The common providers are BackBlaze, Carbonite, and CrashPlan (also called Code 42), and there are others. Cloud server backups are archival backups.

BackBlaze is currently our favorite because it’s easy to set up and use, and costs $5.00 a month per computer, payable annually. Of course the initial backup may take a while, depending on how much data needs to be copied. Thereafter, since on what’s changed since the last backup must be copied, and the backups take place frequently as long as you’re connected to the internet, the backups are quick.

If you need to recover one or two folders, or a few files, from your cloud backup, you can do that right through the backup application provided by BackBlaze, Carbonite, CrashPlan, or whichever service you use. If you need to restore your entire computer, or recover gigabytes of data, the providers will send you your backup on an external drive…overnight.

The upside of the cloud backup is that all your files are stored safely away from your computer…which means that even after a catastrophic loss of your home or office, you can still get your backup and restore to a new computer and be back up and running as of the last backup.

Backup strategies

Simplest: Do regular mirror backups to an external hard drive. This protects if your internal drive fails, or your entire computer fails or is stolen. If your internal drive fails, you can boot your computer from the backup drive and keep working until the internal drive can be replaced. If your computer fails or is stolen, you can restore all your data to a replacement computer, or even boot up a spare, friend’s, or relative’s computer from the backup drive and continue to work. However since the backup drive remains where the computer is, a fire or flood will destroy both the computer and the backup drive.

Benefit from both mirror and archival: We use this method for clients that want the ability to boot up from their backup (like a mirror backup), but also want to safety of being able to retrieve older versions of documents. Get an external drive 3 times the size of the drive you’re backing up. Partition the backup drive as two partitions, one the size of the drive you’re backing up, and one twice that size. Do a mirror backup to the smaller partition, and a Time Machine backup to the larger.

Even safer: User two backup disks rather than one. Keep one on premises for daily backups, and keep the other at someone else’s premises, or in a safe deposit box or vault at the bank. Rotate the drives once a week. That way the off-premises backup drive is never more than a week out of date, but at least you’ll recover most of your data in a catastrophe. We use this method often with clients who don’t want to back up to an internet server.

Safest and our favorite choice: Keep an on-premises mirror and archival backup disk, and also back up to BackBlaze, Carbonite, or CrashPlan. You can boot up from the mirror backup if necessary, retrieve older version of documents and folders from the Time Machine backup on the same drive, and in case of a catastrophe, the internet backup provider will send your entire backup overnight on a hard disk, allowing you to restore everything to a replacement computer. All of this for the cost of an external hard drive, less than $50 for the mirror backup program, and $5.00 a month for the internet backup. Time Machine, the archival backup program, is part of MacOS…it’s free.