We are an online business. Currently we are using DVD's for our backups. The problem is we are running out of space.
We are considering two alternatives here:
- external hard disk drives
- tape drives
We require a copy to be taken off-site every time a backup is performed.
Presently we are backup up tens of gigabytes.
As for your current use of DVDs, if you are a business why are you using hobby level backup media? The choice of hard drives or tapes tends to be a little controversial and even a bit emotional but here is my opinion.
Modern tape technology is extremely advanced and error resistant, with multiple interleaved copies of the data being written to the tape, complete with error detection and correction information. Tapes are extraordinarily robust and although tape drives have a similar failure rate to top quality server grade hard drives, unlike those hard drives the critical part, the bit that holds the data, can simply be used in another drive, something not easily done with hard drive platters.
Hard drives are fragile and unreliable. Of all the components that make up a computer the hard drive is far and away the most unreliable. And that is if the thing is left in one place and not shaken or dropped. You figure how reliable they are as portable media. On top of that they do not use the robust technologies that are so well proven with tapes. Sure, you'll get people telling you how they've had the same drive for 20 years modern drives don't show signs of being capable of such longevity.
If you feel you absolutely must use hard drives at least use 2.5 inch laptop drives, as they are designed to survive more brutal handling than "regular" hard drives.
This has been a topic of discussion here before:
Recommendations for backup (tape vs. HDD)
Recommended Backup Media for Circa 2009?
Think about how many medias you intend to keep in rotation and your desired retention window for old backups and you can start to do a cost comparison between hard disk drive-based backup and tape.
I'd love to see an "enterprise grade" hard disk drive-based backup system meant to replace tape. I haven't seen one yet. SATA drives in non-ruggedized hot-swap carriers is the best I've seen, but I'm not convinced they can handle the workload that good tape technologies (LTO and, to a lesser extent, DLT) have proven they can handle. The "RDX" hard disk drive-based backups (which use 2 1/2" laptop drives in ruggedized carriers) I see frequently offered as the "high end" disk-based backup solution are WAY too expensive per media.
Off-site backup via "the cloud" sounds great, but unless you've got a very small data-set or a very long window to restore, I'm still seeing the constraint of the "drinking straw" sized pipe to the Internet (as compared to LAN bandwidth) as being a major limiting factor. I'd love to do away with local physical-based backup entirely, but it's hard to beat the bandwidth of hand-carrying a tape back from the bank versus your Internet pipe.
You'll find that, for larger numbers of medias, short backup and restore windows combined with crappy Internet bandwidth (where I live, at least), tape still leads hard disk drive-based backup in terms of cost for media. Combined with the rugged and proven nature of tape, I'm hard-pressed to recommend hard disk drive-based backup to most Customers today.
How about backing up over the network to a third-party? if you have to backup to disk then try not to use a cheapo single USB disk, they're less reliable than other systems such a mirrored dual-disk NAS box or a mirrored eSATA drive. Tapes are still in common use and are actually generally more reliable than disks but they have their own problems too (speed and cost/GB being the two main ones). How much data are you talking about and what sort of data; is it flat files such as office documents or 'open' files such as databases etc?
At our office I back up locally with a RAID 1+0 and remotely with Carbonite. No size limit with Carbonite which is awesome.