By Phil Davis
Learn more about backups and backup terminology.
- Bootable Clone Backups
- Versioned Backups – Time Machine
- The Off-Site Backup
- Dropbox and Other Cloud-Based Storage
- Backup vs. Archive
- Do I need a separate hard drive for my clone and Time Machine?
Bootable Clone Backups
A bootable backup is a second hard drive that you can use to boot your Mac when your primary hard drive dies. A clone contains an exact copy of the original source data.
The benefit of a clone is that you have an exact copy of your data, as it existed on your computer. In a pinch, you can take that drive to a similar Mac and boot from it as though you were working from your own machine. A clone drive is also typically faster to restore than an incremental backup drive because it only contains one full copy of your data.
When your primary hard drive dies, you can use it to boot up your computer and use it until you can replace your primary hard drive.
- Buy an external hard drive which is at least the same size as your internal hard drive.
- Purchase and install software such as SuperDuper or Carbon Copy Cloner. Configure the software to make regular backups (nightly would be a good idea).
The downside of a clone is that it is an exact duplicate of the data on your Mac. If you delete a file from your Mac, it will be deleted from the clone. However the current version of Carbon Copy Cloner can be configured to archive the deleted files. One common problem with clones, if your Mac’s hard drive was failing without your knowledge, it was possibly corrupting your data. If you clone that corrupted data to your backup drive, your backup will be corrupted as well.
It is important to “verify” your clone occasionally (once a month would be a good idea). To do this, restart your Mac with the clone drive attached and hold down Option key on your Mac while it is starting up. You should see an option to choose your clone drive. Select it, and make sure that your computer starts up. Once it does, reboot it again the same way and choose your primary hard drive.
If you could only have one kind of backup, it should be a clone. But to avoid the problem of corrupted or lost data, you should have a clone and a Time Machine backup.
Versioned Backups – Time Machine
Time Machine is Apple’s built-in backup solution. Time Machine is ideal for restoring a file or folder that you accidentally deleted, or to undo changes by going back to earlier versions.
- Buy a second-hard drive which is at least 1.5 times the size of your primary drive. The larger the drive, the further back you will be able to go into the past.
- Plug it into your Mac and say yes when asked if you want to use it for Time Machine.
Time Machine stores one version per hour for the past 24 hours, as well as several versions from the past few days and weeks. Time Machine is an easy-to-use and reliable safeguard. However Time Machine backups are not bootable and may not include necessary system files.
The Off-Site Backup
An “off-site backup” is one that exists somewhere other than where your computer is.
You want an off-site backup in case of theft or disaster (fire, flood, etc). If someone breaks into your apartment or house and takes your computer, they are very likely going to take any hard drives they see also. If your home burns down (or floods, or gets wiped out by a tornado or other natural disaster), your backup is going to be just as destroyed as your originals.
The easiest way is to sign up for an online backup service from a place like CrashPlan or Backblaze. For a fee, they will automatically backup your hard drive anytime it is connected to the Internet. I have used both of these services, and they are both excellent.
The biggest problem with an off-site backup is that upload speeds are usually pretty slow and the initial backup may take several days (it runs in the background). However, once it is complete, the backup only involves changes to files and this is usually fast.
Both CrashPlan and Backblaze require creating an account, downloading and installing their app, and letting it run. Both offer a free trial period of at least a couple weeks (which is good since it will take quite awhile for your files to upload anyway). After that it’s just a matter of leaving your computer turned on, even when you aren’t using it, until the initial upload it completed.
CrashPlan can also be used to backup to another computer (like to a friend or relative’s computer in another state) at no charge. While setting that up is outside the scope of this article, it is an option for those who would like to avoid a recurring charge for this.
Another benefit of a paid CrashPlan or Backblaze account is that you can use an iPhone or iPad to get a copy of a file from your account even when you are not at home. Also, if you do lose your computer and backup, both companies will (for a fee) send you a hard drive with your entire backup on it.
You can also arrange to store a second clone backup at the house of a friend or relative. The problem with this is that you will have to update the clone periodically so that the files will be reasonably current.
Dropbox and Other Cloud-Based Storage
If you have somehow managed to avoid hearing about Dropbox, here’s what you need to know: it’s a folder on your computer which syncs to “the cloud” (aka “the Internet).
When you are online, every time you save a file to your Dropbox folder, Dropbox will upload that file to Dropbox’s servers. That file will sync to any other computers which are currently on and linked to your Dropbox account.
If you don’t like Dropbox, there are plenty of other choices out there: Google Drive, Box, Amazon Cloud, OneDrive and others. As long as the service syncs immediately (or reasonably soon) it can be an additional backup for you. It is not one that I would recommend instead of the three methods listed above, but it is one that I use in addition to them.
Apple’s Yosemite (OS X 10.10) includes the new iCloud Drive which function like somewhat like Dropbox. However files stored in iCloud Drive will only be accessible by Macs running Yosemite or iDevices running iOS 8. Dropbox and other cloud storage solutions do not have this restriction.
Backup vs. Archive
I would like to distinguish “backup” from “archive.” Since so many of us are moving from traditional hard drives to lower capacity SSDs in our computers, hard drive space is now at a premium. I have a 256 GB hard drive in my laptop therefore I need to be judicious with my use of disk space. When I’m finished with a project and don’t expect to need it, I will “archive” it and remove it from my primary hard drive.
You can archive data to any number of places, external drive, network attached storage (NAS) or even burn to disc. (I don’t recommend using discs for backup or archive anymore.)
However, files that live only on an external drive must also be backed up because these devices are susceptible to hardware failure, theft, or other problem that would cause data loss. You must also consider these archival sources of data when planning your backup strategy. To keep things simple, I encourage you to consolidate your archives into as few places as possible.
Do I need a separate hard drive for my clone and Time Machine?
Strictly speaking no, you don’t, but with one important caveat. All hard drives die, and that includes backup drives.
If you use one drive for both Time Machine and your bootable clone and that drive has a hardware failure, you will have to recreate both your clone and your Time Machine backup.