Providing Instant Backup

Data Protection Manager gives your customers a solid disk-based backup solution, but it's even better when combined with tape.

• By Don Jones
• November 01, 2005

That absence has given rise to a lively third-party market that offers backup solutions for organizations of all sizes. Now, Microsoft itself joins the fray with Data Protection Manager (DPM), a disk-based backup system that doesn't handle tape or any other type of backup media.

Microsoft is relying on the falling cost of disk storage to make this an increasingly attractive strategy. Disk backups are also typically faster and more reliable than traditional tape-based backups. Of course, your customers can also back up their disks to tape for greater longevity. Most will want this additional level of security and convenience, as it can be difficult to store pure disk-based backups offsite for disaster recovery purposes. In fact, Microsoft's own IT folks back up DPM to tape.

Under the Hood
DPM is an interesting solution that operates a bit differently from traditional backup products. It's agent-based, which means file servers will need a small piece of agent software installed in order to communicate with a DPM server (that adds about 3 percent to 5 percent overhead to the server). The agent grabs files as they change and sends them off for backup. The DPM server itself can use directly attached storage, a Fibre Channel SAN or iSCSI SAN.

Your customers will need tons of disk space, based on the amount of data that changes between tape backups. Microsoft recommends two to three times the space of the data they're protecting. If a customer has 2TB in file servers, for example, they should plan for 4TB to 6TB in DPM storage.

DPM doesn't compress backed-up data, which explains the massive storage capacity requirements. It works with Volume Shadow Copy, which automatically saves changes to DPM three times a day and can store up to 64 copies. That means a customer could, in theory, go for about 20 to 21 days between tape backups before data starts to rotate out of the DPM store.

The software client that comes with DPM extends the capabilities of the existing Volume Shadow Copy client. The DPM client lets users recover previous versions of files, not only from the file server's local shadow copy store, but also from the larger DPM store. This type of self-service makes DPM an efficient solution for single-file recovery, as it helps keep such requests from reaching the help desk. In this regard, DPM is like a super add-on to Volume Shadow Copy. By the way, the DPM client software is also accessible from within Microsoft Office, which is very convenient for your customers.

Currently, DPM doesn't support backups for Exchange, SQL Server, server imaging or client computers, although these capabilities are expected in the second version (due out in 2007 or 2008). Those features will bring Microsoft and DPM into direct competition with most of the third-party backup products.

Competitive Landscape
DPM is Microsoft's first solution that competes directly with products from Symantec Corp. (particularly the products it acquired from Veritas), Computer Associates Inc., Mimosa Systems Inc. and AppIQ Inc., among others. In fact, DPM could be the beginning of the end of a traditionally close relationship between Microsoft and those third-party storage vendors.

Right now, the competitors have a leg up on DPM, in large part because they've been around for so long and have such a large installed base. New products in the disk-to-disk backup space—such as the PathLight VX450 from Advanced Digital Information Corp. (ADIC)—face the toughest competition, because many Microsoft customers will usually choose a Microsoft solution over a third-party tool whenever possible.

One downside to DPM's competitive position is its lack of integration with any form of tape-based backup. That means customers who want tape-based backups for offsite storage will still have to use a third-party solution. Once they've made that decision, DPM may seem superfluous. The PathLight VX450, for example, is a stand-alone disk-to-disk backup device that connects to customers' existing ADIC tape libraries, providing the speed of disk-to-disk backup while retaining tape backup capabilities. Because PathLight integrates tape backup technology, it's automatic. Customers only have to worry about one backup process. With DPM, going to tape is separate from the DPM disk-based backup. DPM could, however, serve as the basis for a fully integrated solution.

The bottom line seems to be that while Microsoft has the right idea for disk-to-disk backup, having a solution that also integrates tape backup is best. That would make both backup and restore seamless, whether the data is on disk or tape. (Microsoft does provide a disk-to-tape backup solution in DPM, but it uses Windows Backup and it's hardly something most customers will care about.)

Marketing and Sales
Microsoft is definitely joining this fight late in the game, and it has to make up for lost time. Its initial marketing positions DPM as an alternative to tape-based backup, which probably won't be the case. It's more likely that customers will use DPM as an adjunct to tapes, because DPM provides fast, immediate backup of online resources and tapes provide additional protection for the disk-based backups. Either way, DPM is a major leg of Microsoft's storage strategy.

Hewlett-Packard Co. is releasing a ProLiant Data Protection Storage Server family, which is a group of NAS devices that use DPM running on Windows Storage Server 2003 for data protection. The devices actually run the DPM server (not the agent), making them a "black box" DPM solution. The box pulls changes from the DPM agents on your customers' file servers, and supports attached tape libraries.

These types of devices are probably the best way to get your customers using DPM. They're single devices that attach to the network, giving customers DPM without the purchase of an additional server (which often leads to concerns about administrative overhead and ongoing support). The ProLiant Data Protection Storage Servers are probably the most plug-and-play implementation of DPM you'll find right now. The Storage Servers include RAID protection and are all completely preconfigured. Other Windows Storage Server OEMs, such as Dell Inc. and iOmega Corp., will soon offer similar devices.

One way Microsoft can be immediately successful with DPM is in environments with lots of data and relatively small tape backup capacity. By removing the need for frequent tape backups, DPM can provide protection for all of the organization's files. Existing tape backup capacity can then be used to gradually back up the DPM stores over time, rather than attempting to back up the entire organization on a more frequent basis. As disk capacity continues to grow and outstrip backup capacity, DPM can be an important gap-closer.

Microsoft's main points about DPM are:

• Rapid and Reliable Recovery: DPM is faster and more reliable than tape backups, which tend to be slow, labor-intensive and less reliable due to media defects.
• Continuous and Efficient Protection: DPM grabs files as they change (or are created). DPM also maintains multiple snapshots of changed files.
• Simplicity: DPM requires very little configuration. Tell it what you want protected, and it just does it—no backup schedules, less end-user interaction and easier usability. Microsoft Operations Manager (MOM) can monitor DPM to ensure continued functionality.

As a partner, you can access several papers on DPM from Microsoft. These papers cover the business case for DPM, as well as include a deployment guide. Microsoft has established a Partner Competency for Backup, which certifies partners who work with these technologies. Partner training in DPM should be available by the time you read this.

Final Word
If you watch your customers' feelings on Volume Shadow Copy, you'll get a good idea of how they'll react to DPM. The two technologies are very similar. Customers will almost certainly want to continue using tape backups, although solutions like DPM may make the need for them less frequent.

As several analysts have noted, however, customers are more likely to prefer a completely integrated solution that combines disk-to-disk and tape backup in a seamless, single-operation solution. Competitors like ADIC currently offer that kind of solution, and OEMs like HP are offering fully integrated "disk-to-disk-to-tape" solutions that provide a robust, complete DPM-based solution. DPM just isn't quite there on its own yet.