What's the best way to back up my computers on-site?

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Ask Ars: What's the best way to back up my computers on-site?

By Casey Johnston | Last updated about 13 hours ago

Question: What is the smartest on-site backup strategy for my house? Time Machine? NAS? External SATA? DVD-R?

There's almost no end to backup solutions and configurations these days, and virtually no excuse for not backing up your computer. Even if you have only a few important files, it's worth it to shell out for an 8GB USB flash drive to store copies on; if you don't, you'll cry out that $20 you saved in anguished tears.

For the most part, backup storage solutions vary on three axes: speed, cost, and flexibility. We'll go over a few different types of storage, and you can determine what's best for you based on your setup.

The most basic solution is to back up to an external hard drive ($75-100 for 1TB) connected directly to your computer using the backup program that comes with your operating system (Backup and Restore Center on Windows, and Time Machine on OS X). Both of these can be automated to back up new files and changes to files on a regular basis, and it's a great, simple option if you only have one computer. Be warned, though: magnetic hard disks aren't known for their reliability, so while having a copy of your critical data on two hard drives (i.e., the one in your computer, plus the external one) is better than having it on one drive, you'll be even better protected if you spread your data around to multiple hard drives (see the RAID discussion, below).

This setup is low on flexibility and cost, but you have some choices you can make on the issue of speed. USB 2.0 is the most common interface, but it's a little slow (40Mbps for file transfers, maxing out at 320Mbps for a bulk transfer). If you want to bump up the speed, drives with an eSATA interface can transfer data at 300Mbps, but you'll need a way to integrate this port into your computer (such as an ExpressCard slot). If you want to pursue this, be warned that eSATA backup systems are usually pretty intense hardware, with multiple drive bays and RAID capability, like this 4TB Cavalry array for $379. FireWire 400 and 800 ports are great for data transfers, at 400Mbps and 800Mbps, respectively, but are only found on Macs.

Someday, USB 3.0 will be a big player on the data transfer field at 625Mbps, but it's not quite widespread yet, and you'll likely have to shell out extra cash to get this interface in both your computer and your storage drive. On the same local storage note, if you only have a desktop computer to back up and have a spare hard drive bay, you can pop a hard drive in there and use it for data storage ($70-90 for 1TB).

If you need to back up multiple computers, in theory, you could just Sneakernet a single portable hard drive between the machines. But if you want a solution with a little more finesse, network-attached storage (NAS) may be a good route to take. NASes are essentially small, low-power computers with lots of storage that connect to a router, and are meant to be accessible over your home network.

NASes are more flexible than single external hard drives, and many come with media sharing features. They vary in both storage size, data writing speeds, and cost ($120 for 1TB, $500 for 6TB and beyond), but if you're looking for fast writes, NASes aren't great, or at best will require some extra equipment: they get about 30Mbps using USB 2.0, and 100Mbps with gigabit Ethernet, which requires that you have a gigabit Ethernet router (around $60-80) connected directly to your computer.

Rather than buy a NAS, you can make your own by buying parts and plugging them all together, or putting a giant hard drive into an old, unused computer, plugging it into your router, then installing FreeNAS on the system. This isn't the user-friendliest of approaches, but it's a fun project if you're a tinkerer.

Likewise, you can make a sort of bootleg NAS by attaching an external hard drive to a stationary computer and then sharing it over your home network for all the other computers to throw backups to, even over WiFi. There's not much speed or security to be had here, and you should bear in mind that the computer will always need to be on. But if those things aren't of concern and you have the materials on hand, it's a fine option.

As noted above, though, it's not good to pin all your backup hopes on a single, failure-prone hard drive. In fact, many techies don't even consider a single hard disk to be a real backup option