Managing Open Files
For most system administrators the challenge of backups is not how to do them, but how to automate them to the greatest extent possible. Files that remain open on behalf of a database application or messaging service are a typical headache. Many administrators run their servers 24 hours a day, seven days a week. There is no good time to shut down applications so supporting databases, caches, and indexes can be backed up.
Some backup software try to resolve this conundrum. Many enterprise-class backup utilities automate backup operations and mark open files for later backup attempts. The problem with trying to backup an open file is that if the physical file is written to while the backup process is in operation, the backup copy is corrupted.
St. Bernard Software Inc.'s Open File Manager is a utility that manages open files and allows backup utilities to transparently copy files that would otherwise be unavailable. Long an established product for the Novell NetWare environment, Open File Manager now works with Windows NT 4.0, Windows 2000, and NetWare version 5.
Open File Manager runs as a layer in-between backup utilities and the systems I/O services. Starting Open File Manager first, a system administrator can run almost any commercial backup software without worrying about skipped files because they are open.
Open File Manager saves the open files the moment the backup process begins. It keeps its own copy of any data that has been modified in the open file. Applications are allowed to continue to use the open file: it’s only when a backup application tries to access changed information that Open File Manager intercedes and substitutes the data from its prewrite cache.
Installing the software on a Windows NT 4.0 server was easy. The software comes in two parts: a Control Component that is always installed, and the System Component that is installed on each server to be managed. The Control Component is the interface used to install and manage Open File Manager. The System Component is the Windows NT or NetWare system module that manages I/O subsystem activity.
We installed the Control Component and the Windows NT 4.0 System Component and were immediately, with no further customization, able to use our backup software -- in this case BEI’s UltraBac -- to gain access to Microsoft Exchange, Oracle, and SQL Server databases. Even with volumes under the control of Microsoft’s Cluster Server, Open File Manager ran flawlessly.
Customization and Performance
The Control Component also permits the alteration of some of the software’s basic configuration. Making changes to the default settings was possible, especially for the volumes where Open File Manager was monitoring files. We liked the ability to exempt specific files from Open File Manager’s work.
St. Bernard includes support for more than 45 backup utilities. This promotes a seamless install of Open File Manager, which then runs backup software without further customization. The software has agent technology preloaded for all mainstream backup software. In our installation, the agents were automatically loaded and enabled for almost every major backup utility in the marketplace. It’s a small quibble, but it would have made sense to allow the administrator to pick the backup utility of their choice rather than install all of the agents by default.
Still, Open File Manager’s impact on system performance was minimal in our tests: With all the default agents enabled, the Control Component and the System Component together accounted for less than 0.5 percent of our system’s activity during backups. The software has a tiny footprint for a utility this useful: Our default installation needed only 7 MB of disk space.
Not Just for Backups
We liked the software’s support for managing open files outside of the context of backup. Open File Manager has an additional agent called the Open File Copy Agent. This feature allows an administrator to log onto the server containing the open file or live database, and then use any traditional file management tool -- the Windows NT command prompt, Windows NT Explorer, or WinZIP -- to copy the live files.
Open File Manager is an essential tool for server administrators faced with the problem of automating backups on machines that are constantly in service. If you use it be prepared to find that your backups take longer -- because they’re finally backing up all the critical data on your system.
Open File Manager 6.0
St. Bernard Software Inc.
San Diego, Calif.
Price: Licensed on a server-by-server basis --
$639 per individual server. Quantity discounts available.
+ Allows system administrators to backup critical databases while leaving applications running
+ Support for all major commercial backup utilities
+ Ease of use is excellent out of the box
+ Support for Microsoft Cluster Server and Windows 2000
+ Low system/disk installation requirements
- Substantial investment for an individual server
- Installation process installs support for all backup software by default.