Seamless Storage with RSS

Maximize disk space—minimize user confusion

The following scenario happens so frequently that it's become one of those "war stories" that administrators like to trade. A vice president is looking for the documents that the staff used to put together the 1995 Annual Report. Nobody who worked on those documents kept a copy on disk. "Why don't we archive this stuff? It's important!" bellows the executive. The lucky administrator then gets the coveted job of explaining why a bunch of 6-year-old documents don't still reside on the network disk.

Wouldn't you love to be able to extend your disk storage space almost indefinitely, without adding disks to your file servers and while still leaving every important document available to users? You can—with Windows 2000's Remote Storage Service (RSS). This nifty feature can monitor the amount of free space available on an NTFS disk and automatically archive files from that disk to a tape library, according to rules that you set. RSS leaves a pointer to the file on the original disk; the pointer includes the filename, last modified date, and file size. The archived file appears to reside on the disk, and fetching the file is seamless to users. And RSS can save your company money: Buying a tape drive (even a robotic tape drive that handles multiple tapes) and plenty of tapes is less expensive than adding hard disks to your servers.

Installing RSS
To use RSS, you need a compatible tape drive, and the disk volumes you want to manage must be NTFS. Win2K doesn't automatically install RSS, so you need to install the service manually. Simply choose the service from the list of Windows components. (You need access to a Win2K CD-ROM or the network share point that serves as your Win2K installation source.) Open the Control Panel Add/Remove Programs applet and click the Add/Remove Windows Components icon. Select the Remote Storage option and click Next. The Windows Component Wizard installs the necessary files and prompts you to restart the computer.

Configuring RSS
To configure RSS, open the Microsoft Management Console (MMC) Remote Storage snap-in. The first time you use the snap-in, the Remote Storage Setup Wizard walks you through the configuration process. The wizard prompts you to complete the following steps:

  • Choose whether to use RSS on all volumes or on selected volumes.
  • Specify the percentage of free space you want to maintain on the managed volume or volumes. When free space dips below this percentage, RSS automatically begins earmarking files.
  • Specify the criteria (i.e., minimum file size and the amount of time since a file was last accessed) that you want RSS to use to determine which files to earmark for archiving when your free-space rule kicks in. Having experimented with RSS, I recommend that you archive large files (relative to typical file sizes for your network). When users select a file, they experience a noticeable delay as RSS finds and opens the file on tape. If the tape is filled with small files, the delay passes from "noticeable" to "seemingly interminable."
  • Specify the schedule you want RSS to use to copy earmarked files to your storage media. This process is called migration, and it doesn't actually delete the file from the original volume—it simply copies the file to storage, leaving a cached copy on the managed volume. When the volume's free space falls below the specified level, RSS replaces the cached files with pointers to the archived files. To prevent the archival process from occurring automatically, you can manually launch the migration procedure rather than set a schedule. (Most cautious administrators first set the copying procedure to manual, then switch to automatic copying after they're more comfortable with the service.)

Maintaining and Optimizing RSS
The RSS snap-in provides many powerful tools that you can use to manage and optimize the service. You can view statistics for your Managed Volumes (as Figure 1 shows), allocate tapes, and monitor performance through a built-in event viewer that automatically filters for events that relate to RSS.

You can tweak the rules that you defined during configuration—a good idea after you've run RSS for a while. You should periodically study the statistics for the volumes and the tapes that you're managing and reconfigure the rules to make sure you get the best possible results from the service. You can add and remove rules for RSS, and you can specify the order in which the service applies those rules—an effective filtering paradigm.

In addition to setting criteria for file size and age, you can specify a list of files to include in or exclude from the archiving process. (Win2K automatically excludes system files and files that Microsoft Internet Explorer—IE—uses.) You can also modify the criteria for the amount of free space you want to maintain on the managed volumes.

You can reset the migration interval at which RSS will copy and cache earmarked files, or you can perform a manual migration. To manually copy files, right-click the volume object and choose All Tasks, Copy Files to Remote Storage.

RSS's feature list is too long to go over in detail in this column, so after you install RSS, I recommend that you examine all the powerful tools built into this component. (For detailed information about how to install, configure, and use RSS, see Douglas Toombs, "Unlimited Storage," June 2000.)

When RSS Isn't the Answer
Sometimes RSS isn't the perfect solution. Witness the story of an administrator who was surprised when a large volume that she was managing with RSS filled up faster than she'd expected. Her rule for free space had kicked in, and many files met the criteria she'd set for file size. However, RSS hadn't earmarked any files for archiving because none of the files met the criteria she'd set for file age. Apparently, enthusiastic workers were creating large files filled with complicated graphic images. Many of the files were new or were opened and modified on a daily basis, so none of them were old enough for RSS to consider for archiving.

To solve the problem, the administrator added a file server, then divided the users' files between the servers. Eventually, the users got past the "new toy" aspect of graphic design and began creating less complicated presentations. At that point, the administrator was able to use RSS to manage both disk volumes.

Although RSS might not be the solution to all your data-archiving woes, it can simplify file storage for you and your users. Implementing this useful tool might mean victory in one more administrative battle.

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