Backup Glossary: Pick Two Types

by Jerry Stern
PC Systems Consultant,
Westminster, Maryland

I’ve explained image backups here a few times, but a refresher is due: An image backup records the contents of an entire hard drive. It’s like a snapshot, so that if the drive stops working, the image can be copied back onto a replacement drive.

It’s a misleading term, because backup software products, mostly, don’t have that option. They each have a few options, and then the large-business products add more. It’s complex, but remember that two of these backup types are all you need, with one of them out of the building.

  • File Sync:  This is an uncompressed copy of a set of folders to a backup location. It’s a cheap version of replication, for documents only. For a very small network, the drive used as the backup can be switched into use as a very basic file server in a few minutes.
  • System Backup: Usually, this is a backup of Windows, the ‘C:’ partition, and documents and data stored in the default ‘Users’ folders. It doesn’t include the contents of other drive letters. This works as an image backup if the computer’s drive has no additional drive letters.


  • Disk Backup: This is close to an image backup, but usually not reliable for bootable drives like C:, because not all backup software will restore the boot settings.
  • File Backup: Choose your folders. It’s a very targeted backup.
  • Replication: This is a virtual copy of a server, usually saved to a NAS/network-attached drive, or a SAN/storage-area-network (same thing, but more of them). When a server fails, the virtual copy can replace the original as an online (local or cloud) copy of the original server, and work well enough to make do until a new server can be put in place.
    Advantage over the other backup types: Speed, under 5 minutes downtime. Disadvantage: Cost: Around $200 per month for a single server, plus a pricey high-end network-attached drive.
  • Cloud Backup: That’s backup to backup servers on the internet, and it can run either nightly, or it can backup documents all day as you edit, and generally keeps multiple versions. Best for document backups, but not practical for image/system backups, because the volume of data to upload would be too large in most offices; it would use up all your data allowance on your internet connection, even on cable, which is usually limited to 250 Gb per month.

Way too many options, right? Again, most offices should pick two.

The choices are based on a few factors:

  • What risks you expect: Drive failures and cryptoware are the same problem, on one computer–everything is missing. Both require full-image backups and document backups. For a small network, replication of the file server is a better strategy.
  • What you back up: Documents and databases are handled in different ways, and the best backup for ‘nothing but spreadsheets’ is not adequate for a database.
  • How much you back up: How many users’ documents need to be backed up.
  • How much down time you can afford: How long until you need to be back in business after the lightning strike?
  • How many offices you have: Two offices can backup to each other, like a private cloud.
  • How much data you can afford to lose: If your answer is ‘one day of data entry’, nearly any nightly backup will work. If it’s ‘one second’ of work, you’re probably running a multi-national airline, and there are multi-continent real-time synchronization and automatic load-balancing and failure management systems for that, with more acronyms and unclear names.