Managing and Mirroring Backups

Storage Resource Manager 1.0 and Media Mirror 1.0 from HighGround Systems

The backup and resource-planning solutions market continues to grow, and understanding why isn't difficult. Imagine that your system backup fails: What are your options? You can forgo your scheduled backup and keep your fingers crossed that nothing happens to bring down the system, or you can shut down your network and effect an immediate backup. Neither option is desirable.

Most businesses carry insurance against unexpected catastrophic events, but what can systems administrators do to defend their systems against disaster? The answer is, "Plan, plan, plan." In this month's installment of the Windows NT Lab's ongoing review of backup software, I look at two solutions from HighGround Systems that help systems administrators plan, develop, and conduct effective backup procedures.

Storage Resource Manager (SRM) helps systems administrators manage their resources by giving a consolidated view of the status of storage on a network's client and server systems. By displaying statistics about capacity, utilization, system health, and trend reporting, SRM can help you determine whether your backups are running effectively, whether you need more storage capacity, and which users take up the most storage space. When you use SRM, you can pinpoint your current backup problems and predict what they're likely to become in the future.

Media Mirror is a fault-protection solution for organizations that use tape drives for backup and recovery. It creates a mirror copy of a backup session, which lets you double your protection by storing identical backup records in separate locations. Media Mirror offers backup and recovery protection by creating a mirror (or virtual tape drive), making two or more physical tape devices appear as one unit in the mirror, then working with existing backup software to write identical backup data to each tape drive in the mirror simultaneously.

Storage Resource Manager 1.0
Before you can use SRM 1.0, you must install Windows NT Service Pack 3 (SP3), Internet Information Server (IIS) 3.0, and Microsoft's Active Server Pages. (You can get IIS 3.0 and Microsoft's Active Server Pages from the SP3 CD-ROM.) The version of SRM I tested--1.0--does not support IIS 4.x; however, version 1.01, released after I concluded my tests, does include support for IIS 4.x. Officials from HighGround Systems claim that future releases of SRM will support IIS 4.x. I tested SRM on the Lab's 200MHz DTK Dual Pentium Pro machine, with 128MB of RAM and a 4.2GB hard disk.

Installing SRM was easy with the installation wizard, which automatically sets up the SRM domain local group and server logon account. You can also create the local group and server logon account manually. After you install SRM, you must reboot to engage the IIS Web server and other services.

Before you can use SRM, you must install SRM Agents on each client computer (I used two HP Vectra P-120s with 32MB of RAM for my test client machines). Fortunately, the only difference between installing the server and the agents is selecting either "Server" or "Agent" when those options appear during the installation process. You can't install agents across the network with SRM 1.0, although HighGround Systems plans to include this capability in future releases of the software.

When I installed the SRM Agents I noticed a lot of disk activity. But I realized that during installation an agent makes a call to the SRM Server, which returns the call and begins an initial scan of the agent. This scan records a variety of information, including information about RAM, disk partitions, disk space, file type (FAT or NTFS), processor speed, and about 60 other statistics. It took me about 20 minutes to set up the SRM Server and 10 minutes to install each SRM Agent.

After I installed the SRM Server and Agents and my test system was up and running, I accessed the SRM Server with my browser (I used Internet Explorer 3.02). SRM's user interface is well organized and tailored to a Web-page model. I was impressed by how well I could manage each client computer with SRM. The product's interface is pleasant to look at and intuitive. It makes gathering data easy for smaller networks.

You update the SRM Server's database by using its scanning program, which prompts the server to make calls to all online agents and gather their current data. To access the scanning program, I clicked Options on the SRM toolbar, which opened a vertical taskbar. After clicking Change Scan Time on the vertical taskbar, I was disappointed to find that my only option was to set one scan time, which remains in force until I change it. For example, if I set a scan time of 9:00 a.m., the SRM scanning program initiates every day at 9:00 a.m., until I change the time. If I want to run two scans a day, say at 9:00 a.m. and 5:00 p.m., I must set each scan time manually, twice a day, every day. On small networks with a low volume of activity, this limitation might not pose a problem. However, on enterprise networks or networks requiring close resource tracking, systems administrators need the option to schedule multiple scanning times and frequencies.

After SRM's scanning program gathers statistics from the client computers, you can sort the statistics by domain, computer, disk, partition, or user, and then view them in text form or in various chart formats. For example, you can sort data under a domain heading by creation date over a specified period, which lets you determine whether the volume of created files in the domain is increasing.

You can assess file vulnerability by using SRM to gather information about files that are modified but not backed up. With an SRM Domain By Computer File Vulnerability report, which Screen 1 shows, you can identify files that are not backed up within defined time periods. SRM defines 5 time periods: less than a day, more than a day but less than a week, more than a week but less than a month, more than a month but less than a year, and more than a year. When you look at the file vulnerability data that SRM gathers, you can tell whether users are backing up certain classes of files on a regular basis. You might discover that users are regularly leaving certain types of files open or that your backup software isn't working properly.

SRM stores all its data in one database, and I wondered what would happen to the database if the server program or agents were corrupted or missing. To find out, I deleted the main SRM executable and a few other files, then reinstalled the SRM program files. I was pleased to see the database emerge unscathed. SRM stores its database in a separate file from the program files, so the database remains intact even if you must reinstall the SRM program files.

SRM 1.0 is one of the first storage-management applications on the market, but it is missing important capabilities. For example, the program lets you manage only one domain and no workgroups. HighGround Systems has added support for multiple domains and workgroups in SRM version 1.01. Another limitation is that SRM doesn't let you set threshold limits (i.e., maximum storage capacity for a client computer's disk) with associated pop-up warning messages that alert you when the client computer exceeds the threshold. Without a threshold-monitoring capability, SRM requires systems administrators to review agent-computer statistics individually. HighGround Systems plans to include threshold monitoring in SRM 2.0, which is due for release in late March 1998.

I discovered another limitation in SRM when I tried to set a new scan time. I received an internal application error that locked in the default scan time and wouldn't let me change it. I couldn't pinpoint the source of this problem, and eventually it went away, to reappear when I reinstalled SRM. Given enough time and information, I'm sure HighGround Systems could have solved this mystery. Unfortunately, I had to move on.

SRM has the potential to be a useful tool in planning and administering computer networks. SRM is easy to use and provides a wealth of data-gathering options. I feel that SRM has great potential, but because of the problems I experienced with the version I tested, I advise you to download an evaluation copy of SRM and test it in your own environment before you buy it.

Media Mirror 1.0
The Media Mirror program has three components: Media Mirror, Media Copy, and Media Compare. Media Mirror is the central program, and it manages the mirrors you create between tape drives (Screen 2 shows the mirror between two tape drives in the Media Mirror properties window). Media Copy copies the contents of one tape drive to a second tape drive while preserving the data on the first drive. Media Compare compares two or more mirrored tape drives to confirm that their contents are identical.

I installed the Media Mirror program easily with the installation CD-ROM. You can't install Media Mirror across a network but must perform the installation process at each tape-device server. Media Mirror's product documentation states that the tape drives, media, and adapters you intend to use with Media Mirror must be identical, regardless of whether you use a single or multiple SCSI bus. (Identical means that all matching components in a mirror must be the same make and model.) If you already have heterogeneous tape devices in place, you must invest in identical equipment before you can use Media Mirror.

The most important step in the installation process is creating a mirror between two or more tape drives. For my tests, I used HP SureStore DAT24 units. The Media Mirror setup program automatically detected the HP units, and I easily created a mirror between them by selecting the mirror-creation option during the installation. The program took a short time to create the mirror, then it prompted me to reboot the system. Creating a mirror after the Media Mirror installation process completes is equally easy: I opened the File menu and selected the New Mirror command. An easy-to-follow wizard walked me through the steps of choosing the drives I wanted to mirror, and in less than a minute my new mirror was set up. (Note that you can include each drive you want to mirror in only one mirror.)

When you run a backup with Media Mirror, the media you use must either be blank or contain identical data. The first time I tried to back up with Media Mirror, my media did not contain identical data. The program prompted me to run either the Media Copy utility (to replicate the data on the master tape, which you designate, to all other tapes in the mirror) or the Quick Erase utility (to erase all the data on the mirror's media).

HighGround Systems has approved the use of Seagate's Backup Exec, BEI's Ultrabac, and Microsoft's Windows NT Backup for use with Media Mirror, although the company says Media Mirror should work with any Win32-compliant backup and recovery application.

After I ran Media Mirror successfully with Backup Exec and NT Backup, I wanted to test the effects of using backup software that isn't on HighGround Systems' recommended list. For that purpose I chose Stac's Replica, a program that replicates data from one tape drive to another and that displays the data-transfer rate. Media Mirror ran efficiently during Replica's backup and recovery phases, and I could easily track the simultaneous data writing. I turned off one of the two mirrored tape drives about 20 minutes into Replica's backup process, and the other drive continued unimpeded.

Backups slow when you mirror data because you must add multiple tape devices to one SCSI bus. To optimize speed when you use Media Mirror, HighGround Systems recommends that you install each tape drive on its own SCSI bus. For my test, I installed two tape drives on one SCSI bus, and my backup rate was about 25 percent slower when I used Media Mirror than it is when I back up with one tape drive. Dropping from a backup speed of 60MB per minute to 45MB per minute might not affect small companies negatively, but this reduction can have a major effect in a large enterprise.

Media Mirror lets you use the virtual drive (or mirror) in recovery procedures. When you use the same recovery procedures your backup software recommends in conjunction with Media Mirror's virtual drive, Media Mirror's mirroring capability protects against media or drive failure. In my tests, Media Mirror continued my backup software's recovery process even after I turned the power off for one of the two mirrored tape drives halfway through the recovery.

Media Mirror is easy to use, but it has limitations. The biggest limitation is the hardware requirements--you must use identical tape drives. You can purchase Media Mirror bundled with two Exabyte or two ADIC tape drives, but I'd like to see it handle heterogeneous tape drives, because that would expand this product's possibilities. For now, potential users must decide whether living with an investment in Media Mirror and whatever extra hardware is necessary to use it is easier than living with the potential risks inherent in single-device backups.