Not having a backup is risky - but Time Machine is often not enough.
Having a backup strategy in place is smart, but your backups should be robust enough to meet your needs. Here's a quick list of what a well-designed Mac backup system should be able to do for you.
Rolling back changes to files & getting lost ones back
- Versioning allows you to roll back changes to a document, or restore an earlier version. Since Mac OS X 10.7 Lion, Apple has built-in versioning for documents created on Apple applications - such as Keynote, Pages, Numbers, Preview, and even Textedit- and it has improved in Mountain Lion (10.8) and the new Mavericks (10.9). However, documents created with other applications (such as MS Office, or Adobe Creative Suite) don't have built-in versioning yet.
- Restore files: with a backup system like Time Machine, you can restore files that were deleted earlier- and you can restore previous versions of current files.
Staying productive after drive or system failures
- With Time Machine being free and available on all recent Macs, it's a great choice for versioning and file restoration. Time Machine can also be used to restore an entire system - however, it's not very robust, or fast. Plus, you can't boot from Time Machine.
- Cloned boot drives: It can happen that your Mac's boot disk fails; in this case you should have a clone of your boot disk set up. It contains automatic duplicates of your system, so you can easily boot from the clone and get back to work. Also, restoring your system is much faster with a cloned disk.
- RAID units are very useful for both work stations and backup systems to prevent against data loss when one or more drives fail, by keeping data duplicated at all times. This way, you can get over drive failure without losing your data, or time working.
When all else fails, literally
- Off-site backup: Keep copies of your files, or even your entire system setup, off-site to protect against loss of your on-site data (due to accident, theft, or other event). The old fashioned way is to create duplicate on-site backups, move one off-site, and regularly rotate over time.
- Sharing services: Sometimes it's sufficient to save your most important files to a free online storage solution like Dropbox, or Google Drive. These services don't provide a lot of space on the free plan, but you do get the benefit of accessing your files from other computers, iPhones, and iPads, and even PCs. If you don't have a lot of specific files you need to back up, these free or low cost services might be an option for you.
- Cloud backup: For a more comprehensive solution you may want to consider online backup services such as BackBlaze, CrashPlan, or even Amazon S3/Glacier storage.
- Having a backup isn't the same as maintaining an archive: archival data doesn't change, and is infrequently accessed. It's important, but not critical to doing work right now. And, archives can take up a lot of space, and can be costly.
Storing archival data on external storage (hard drives, or disks such as DVD or Blu-ray) allows you to free up space on both your local system and your backup. In some cases, you can use cloud storage services for archives, especially if you infrequently need access to the data, but want it secure and off-site.
- Use a versioning backup system like time machine to roll back changes.
- Keep a local clone of your boot drive to get back to work quickly.
- Secure working data drives in RAID arrays to prevent data loss due to drive failure.
- Keep off-site duplicates of archives and of working data.
- Tell apart archival data from working data to save space & cost.