The simplest backup option is to plug a USB drive into the NAS to copy the folders and files that are the most critical to your business. All of the NAS boxes I reviewed include USB ports, and most have eSATA ports. Some even have handy buttons on the front for automating these backups. However, if you need to back up multiple terabytes of data, plugging in an external USB is hardly the best option.
Not long ago, you would look to a software solution to perform regular backups of your data to a tape drive. Tape is still a valid solution, and vendors such as Netgear make it clear that they have partnerships with many of these software makers (Symantec, Acronis, and StorageCraft to name a few).
Today, disk-to-disk backup is the clear solution in this market segment. Basically, this requires you to deploy two NAS boxes and have them sync to each other. In the individual reviews, I went into more depth on some of the more elegant replication solutions by Iomega and Netgear. Replication in QNAP is not quite on par with Iomega and Netgear, but it's a cut above Synology and Thecus. For these devices, replication is done using rsync.
Rsync allows you to synchronize your files automatically to another box. Instead of copying all of the data each time, rsync copies over only the changes or differences, minimizing both bandwidth requirements and copy time. Rsync is a perfectly good way to back up the NAS, but it is harder to set up than the replication solutions from the likes of Iomega and Netgear. These make NAS backups a snap even for nontechnical users. In Netgear's case, it also provides the ability to manage several NAS boxes from one Web-based interface to do file replication across multiple sites (albeit at additional cost).
Then there's "cloud backup" -- using backup software that copies the data on the NAS to a cloud storage service. Typically, these services charge a monthly fee that depends on the amount of data you need to store on their servers. Procedures are in place to ensure the privacy of your data via encryption and security policies. Iomega and Netgear use their own cloud storage solutions, but other NAS manufacturers such as QNAP offer backup to third parties such as Amazon S3 and ElephantDrive.
NAS shoot-out: Advanced features iSCSI (Internet Small Computer System Interface) is a feature that many small businesses should keep in mind. Even if you might not use it today, it offers flexibility you might very well appreciate in the future. In a nutshell, iSCSI gives the illusion to a server that it has locally attached storage when that storage is in fact running off the NAS. It is a perfect way to consolidate your data in one location while also giving your Web server or database server the "local" storage it requires.
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