First, let me say that anytime you get ten network engineers in a room and ask for the best way to do something, you'll likely get at least ten different answers. That doesn't mean they're all wrong, just that based on each one's experience a particular strategy has become their preference.
MBS' Recommended Backup Strategies
We did some fairly heavy research not too long ago on the subject of backup systems. There are lots of possibilities, but we found that tape was still preferred by most of corporate America that had small-to-medium sized networks-- and even some very large systems like digital media archives.
Here's what we learned:
- Large networks rely on SAN devices (Storage Area Networks) in larger onsite and offsite datacenters, and their replication capabilities make backups unnecessary. Those devices typically cost a minimum of $25-$30 thousand each, and larger units cost six figures. (Some people try to accomplish SANs on the cheap using Drobo and Buffalo drives, but they're unreliable; in our opinion they're not enterprise grade.) For our largest clients we recommend using SAN devices.
- Online backup is good for restoring single files or folders, but is inadequate for restoring entire servers in a disaster. And disaster recovery is something that must be planned for. This is the strategy we only recommend for our friends' home computers.
- External hard drives seem like a good idea except that they have many moving parts that, when transported offsite (which should happen often as part of the disaster recovery plan), can-- and often do-- fail. The manufacturers will replace them under warranty, but without any data on them; not good if that happens during a disaster recovery scenario. We never recommend this strategy.
- Tape technology continues to move forward in development. Our clients typically only need LTO5 or LTO6 (Linear Tape-Open) specs (1.5tb and 2.5tb native capacities), but LTO7 - LTO10 are slated for release. I'll be surprised if they get there, however, because an organization with that much data will usually be at the size where they're investing in SANs.
In our datacenter we use SANs that send their backups to another enterprise-grade device called a NAS (for Network Attached Storage) that has large capacity. We use that strategy in the datacenter because we're not there to change tapes on a daily basis.