As storage capacity needs grow in SMBs, disk is increasingly being used as a backup storage target. In this FAQ, Executive Editor and Independent Backup Expert W. Curtis Preston, discusses the role of disk-based backup in the SMB space. Curtis takes a closer look at the benefits and cost differentiators of moving from tape to disk for data backup. His answers are also available to download below.
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Especially for SMBs, the benefit of using disk instead of tape for backup is a significant change in reliability. It's true for the enterprise, but for the SMB market, tape has often meant buying much less expensive tape drives than are typically purchased in the enterprise. So products like digital audio tapes (DAT) and Travan Tape Backup Drives are fine, but they don't offer the level of reliability that you're used to in the enterprise space.
The biggest benefit for the SMB/midmarket space is reliability. Speed is also benefit to a similar degree, but with the amount of data we're talking about, it's not the primary consideration.
Because the system is on disk, it can also be replicated. The amount of data that most SMBs back up is small enough so that it's pretty easy to back up this data to one system and then using data deduplication or replication, replicate that data to another site which could, depending on the size of the company, be the home of a senior executive or it could be an outsourced vendor that does collocation. It could also be another location, in the case of a larger-sized SMB.
Going to disk makes all sorts of things possible. The No. 1 thing it gets rid of is a problem that many companies have. Where SMBs don't typically have dedicated backup and recovery staffs monitoring their backups, years can go by where their backup system, which is often a single system DAT drive or a very small autochanger, is running, and when they go to restore, they find that the system hasn't been very reliable.
When you're comparing the cost of disk and tape, you must remember to compare the cost of both the media and the drive. A lot of people forget that and they compare the cost per megabyte of a tape and the cost per megabyte a drive. Make sure to remember to bring in the cost of the tape drive and any automation systems you need as well.
But oddly enough, when we start talking about that SMB space, we're often talking about less than a terabyte of data. I just bought a 1.5 TB disk drive for $120. For half of that, I can only buy a single tape for a lot of the tape drives that are out there, and it's not going to fit a terabyte of data.
So the cost comparison for an SMB, is often really in favor of disk because they don't need this massive performance; they just need enough storage to hold things. That can often be provided by a portable disk drive or an external disk drive. Or, it can be a small array, something like a Drobo Robotics Inc. system, which with a 4 TB disk drive, provides you 3 TB to 4 TB of extremely affordable backup storage. Compare that to the cost of a three to four tape system, and I think you're going to come out in the favor of disk, especially when you start thinking about the cost of automation.
Another thing to consider in cost, which is especially true in the SMB space, is the potential of outsourcing your entire backup operation. There are a myriad of companies that for a certain dollar amount per month will, simply make backup not your problem. You simply install a piece of software and they make sure the backup happens. If the backup doesn't happen, they let you know, which is really all you need to know. It's often more than you would know when creating and managing the backup system yourself.
Make sure that you look at outsourced backup companies that can back up your data directly to an offsite location or can back up to a local server that then replicates to an outside server for faster recovery.
Data deduplication is pretty much the one to talk about. Dedupe is here to stay and it is reality for businesses both large and small, but especially for the SMB. For large enterprises, data dedupe is here, but for companies that want to back up hundreds of terabytes a day, they've got some problems that haven't necessarily been solved by the vendors.
For the SMB, pretty much any of the dedupe products that are out there are ready to go. Their performance requirements are different and their capacity requirements are different, so there are products that specifically aim themselves at the SMB space and are not interested in the enterprise space.
A lot of these are dedupe products; from dedupe software that you can run as a backup client on your system to back up all of your servers, to a single system that can then replicate to another system. If you want to continue to use your current backup software and do replication, you could buy a small dedupe system that will then replicate your backups offsite and you can continue to use that software.
Assuming that this is a problem, I would recommend investigating RAID systems to increase the bandwidth to disk system by spreading the I/O load across multiple disk drives instead of a single disk system.
Beyond that, because you're going to disk, you might consider less frequent full backups. If all of your backups are on disk, restoring from several incrementals or one full is often the same speed. So it's not necessarily increasing the speed as much as it is decreasing the amount of time it takes to for a backup to occur.Check out more backup resources from Curtis Preston.
W. Curtis Preston (a.k.a. "Mr. Backup"), Executive Editor and Independent Backup Expert, has been singularly focused on data backup and recovery for more than 15 years. From starting as a backup admin at a $35 billion dollar credit card company to being one of the most sought-after consultants, writers and speakers in this space, it's hard to find someone more focused on recovering lost data. He is the webmaster of BackupCentral.com, the author of hundreds of articles, and the books "Backup and Recovery" and "Using SANs and NAS."
This was first published in February 2009