Qstar vs. Allstor: Full-spectrum Juke Management

By Lowell Rapaport

As the demands on storage increase, there is a strong incentive to apply jukebox management applications to a range of storage devices. Qstar and Allstor have responded with storage management systems that embrace WORM, MO, CD, tape and, in Allstor’s case, DVD.

Support for tape is a real plus. There is no form of storage that can match tape libraries for sheer capacity combined with low cost per megabyte. Combine a tape library with a hard drive or RAID subsystem for cache, and you can put a huge amount of archive storage online. Enterprise Library Manager (ELM) from Allstor (www.allstor-sw.com) and HSM 4.7 from Qstar (www.qstar.com) transform a tape library from a glorified backup system into a real solution for large, albeit relatively inactive, archives.

We brought HSM and Enterprise Library Manager into our lab for a closer look at two of the broadest-ranging jukebox management systems available. Both systems delivered good performance and, with some tradeoffs, flexible management of storage tasks. DVD support gives Allstor an edge for those eyeing this cutting-edge media, and other differences emerged in our testing that pushed it over the top, though narrowly, as our Editor’s Choice.

Of course, these aren’t the only jukebox management systems to choose from. “Four More Alternatives for Juke Management” outlines the latest upgrades implemented by or soon expected from other jukebox management software vendors.

Qstar HSM Puts A Window on Storage

Qstar HSM 4.7 Fort Walton Beach, FL 850-243-0900 Operating Systems: Windows NT, Unix Disk formats: MO, WORM, CD Tape formats: DDS, DLT, AIT Remote Management: Yes Comment: Easy to use. Flexible and capacious cache management. Fast read and write speeds, but slow cache flushing, disk mounting and other CPU-intensive operations. No DVD support. Tape library support is for DLT and AIT only. DDS supported at the drive level only. NTFS support to be added in December. Price: $2,100 - $12,000 ProductInfo 260

Working with Qstar is relatively simple, but it requires multiple steps. A tabbed window gives you access to the jukebox management functions; instead of pulling down menus, you simply click on a window tab. Each sub window has up to several tabs within it for additional functions. The approach gives you the impression of a massive Windows NT control panel.

After installing the software, you click the Devices tab to install jukeboxes, libraries and drives. Disks and tapes are added through a Media tab=2E We liked the progress report that Qstar offered as each piece of media was formatted. Most jukebox management systems format media in the background and give you no indication as to how soon formatting will conclude.

Once you’ve added media to your jukebox or library, you can create virtual disks using the Integral Volumes tab. Separate tabs within this window let you add media to a volume, mount volumes to your network and manage the cache. You can add any number of discs (or cartridges) to a volume, and if the volume needs more disk space, it will take available unused media.

Qstar lets you cache volumes independently with up to 2 gigabytes (GB) of cache for each volume. Cached files are migrated to optical media automatically. However, if you want to flush the cache periodically, you must use commands from a DOS window since the program’s user interface doesn’t yet support the scheduler portion of the software.

Qstar doesn’t mount volumes to Windows directly. You have to use Windows Explorer to mount them from a separate Qstar server that functions from within your Windows NT machine. This means that Qstar volumes will have their own domain on your network. It also means that you can’t use NT’s built-in security features to manage access to volumes. This limits Qstar’s usefulness in environments demanding robust security.

Qstar was a good performer, with read and write speeds nearly equivalent at about 250 kbytes/sec. Usually you’d expect the write speeds to be slower. Once the cache filled to its default setting of a 500 MB, CPU-intensive operations such as mounting a volume or flushing the cache caused a noticeable slowdown on the single-processor, 300 Mhz Pentium II server used in our test. A newer Pentium III or, even better, a multiprocessor machine should easily cope with these demands. If you’re not ready to upgrade, Qstar users would be wise to schedule high-demand operations for off-peak hours. Given the low cost of computers today, it may make better sense to let Qstar run on its own dedicated server.

There is a trend for jukebox management systems to support standard disk formats such as NTFS and UDF. These “open” formats let you interchange disks between systems and read media outside of the juke management environment, but proprietary disk formats still have their place. For one thing, if you are going to rely on WORM storage, you must use a proprietary disk format. NTFS doesn’t support WORM media at all. Another factor is that for many applications, proprietary disk formats are frequently faster than comparable standard disk formats.

The latest release of Qstar, expected to ship later this month, will incorporate support for NTFS. You’ll still be able to choose Qstar’s proprietary formats if you value system performance over media portability. Qstar has yet to set a firm date for adding support for DVD.

We really liked Qstar HSM. It was easy to set up and its cache management was straightforward and powerful. We especially liked the adjustable cache that maxes out at an impressive 2 GB, but you’ll need a fast server to speed cache flushing and other high-demand, cache-killer operations.

Allstor Adds Versatility To the Menu

Allstor Enterprise Library Manager Rancho Santa Margarita, CA 949-766-3200 Operating Systems: Windows NT, Unix Disk formats: MO, WORM, CD, DVD-ROM, DVD-RAM, PD Tape formats: DLT, AIT, NCTP Remote Management: Yes Comment: Straightforward user interface eases multitasking. Offers the widest support of optical disk formats including DVD. Supports NTFS and UDF as well as its own proprietary disk formats. Average read/write speeds but fast all-around performance. Lacks manual cache management options. Some tape support still in beta. Price: $2,000 - $29,900 ProductInfo 261

One of the most striking differences between Allstor’s Enterprise Library Manager (ELM) and other jukebox management programs is that the user interface is nothing more than a menubar. Activating any of the commands on the menubar brings up a separate window. This, too, contrasts with other applications that execute all operations from a single window. The approach underscores this system’s ability to run multiple tasks simultaneously.

To administer ELM, you start the Jukebox Control Program from the main menubar. This presents a new tool bar with pull-down menus for checking the status of the jukebox, importing and exporting media, off-line volume management and utilities concerned with rescanning media installed in a jukebox. We found the arrangement easy to understand, and we especially liked the fact that the Jukebox Control Program doesn’t use a lot of screen real estate. Some of the Unix-like user interfaces — such as those used to access information on the jukebox — could stand improvement, but overall, the system’s look and feel was very good.

If you wish, the Enterprise Library Manager will install an Apache Web Server that will enable remote management. With the server installed, administrators can log into the system using any browser over a LAN, intranet or the Internet. System administrators who don’t want to trek in to work to handle a small glitch can execute repairs remotely.

One thing absent from ELM’s interface is provision for cache management. There are no controls for changing the cache size or location. This could make it difficult to streamline the system for certain applications and different workloads. There is no write cache. Files are written directly to the jukebox. The read cache ranges up to 46 GB, but this has to be customized (i.e., coded) through the application program interface. The read cache default is eight megabytes.

Enterprise Library Manager can operate as a system service for ease of use or as an application for ease of maintenance. Either way, the usual library functions are present, including disk and volume mounting, offline management, media import and export, etc. ELM will manage CD, DVD, MO, WORM and tape libraries in a choice of formats: Proprietary, UDF (version 1.02), NTFS or Microsoft tape.

While proprietary disk formats can be faster than NTFS, they are less than ideal for rewritable media. Typically you can remove a file from the directory of a WORM formatted rewritable disk (as opposed to true ablative WORM), but the space can’t be reclaimed unless the disk is reformatted. Tools for reclaiming this space are provided with these systems, but they are cumbersome to use and are not as clean as a true rewritable disk format. Of the two jukebox management systems tested here, only Allstor permitted disks to be formatted with truly rewritable formats, but Qstar will gain that capability with the imminent release of NTFS support.

In our performance tests, Allstor was only about one third as fast as Qstar in both read and write speeds. However, overall speed under heavy use was better since ELM didn’t have to stop to flush a write cache. Nor did it slow down other processes being run by the computer. If you can’t put jukebox management on a separate machine or employ a high-end server, you’ll get better overall performance from Allstor’s Enterprise Library Manager. Add in support for DVD-RAM and the additional file formats, and you have the ingredients of an Editor’s Choice.

Is there room for improvement in these products? Of course. We’d like to see both products combine different storage technologies (e.g., disk and tape) in a single volume. HSM needs full support for NTFS and for the latest UDF 2.0 standard. HSM also needs more efficient cache management. For now, Allstor represents the best combination of features and performance.

Four More Alternatives For Juke Management Five months ago, we tested Disk Xtender from OTG, SmartStor from Smart Storage and Ascent Storage from Kofax. At the time, elements like DVD support were in their infancy, and these developers were just beginning to support new formats and a wider range of media. Now the beta trials are through, and you’ll find even newer functionality in these and other storage software products. In our last test, OTG (www.otg.com) was leading the way in moving from jukebox management to broader storage management. Now in version 4.2, Disk Xtender supports AIT tape and DVD-RAM. With AIT support, Disk Xtender works with all major tape technologies, DDS, DLT, AIT and SLR. Disk Xtender supports DVD-RAM with a proprietary format rather than UDF. Two other features added by OTG are storage compaction and automatic volume expansion. Available on a number of storage management systems, compaction defragments files on rewritable media and reclaims space taken by deleted files. Automatic volume expansion enables Disk Xtender to add additional blank media to storage volumes as demand increases. SmartStor (www.smartstorage.com) was already supporting DVD-RAM in our last test, and they subsequently progressed to the UDF 1.5 format. Smart Storage now promises full support for UDF 2.0 by the time this article sees print. UDF 2.0 allows full read, write and erase capability with CD-RW, DVD-RAM and (still unavailable) DVD-RW. Smart Storage also has support for Pioneer’s DVD-R, which is now available in a jukebox also from Pioneer. These recorders can be used just like CD recorders with Smart Storage’s new software. Version 5.0 of Ascent Storage from Kofax (www.kofax.com) adds DVD-RAM support. According to the company, jukebox manufacturers and consumers are settling in on DVD-RAM as the standard for rewritable DVD storage for the enterprise. Kofax is specifically supporting Plasmon’s DVD-RAM jukeboxes, and the company promises support for others as they become available. We recently went through a preliminary examination of Investor, a WORM- and MO-oriented system from Pegasus (www.pegasus-ofs.com), but we decided to hold our testing for a major upgrade expected in the first quarter of 2000. Enhancements will reportedly include volume spanning (across multiple disk surfaces), more flexible caching and support for rewritable disks and a wider variety of storage technologies.