Mainframe VTL Opens Up

Virtual tape library (VTL) products and users have proliferated on open systems in the past few years as companies seek faster and more reliable methods of backing up data. (See Users Ponder Tape Independence.)

You'd never know it from all the hype around VTL, but the trend actually started on the mainframe with integrated systems from IBM and Sun/StorageTek. Other options include VTL mainframe software from CA and Diligent, and appliances from Bus-Tech and Luminex that back up mainframe data to disk.

Bus-Tech is beefing up its mainframe virtual tape offering this week with its Mainframe Data Library (MDL), a larger version of the Mainframe Appliance for Storage (MAS) system it has sold since 2002. (See Bus-Tech Intros Mainframe Storage.) The MDL consists of two or four nodes with Ficon or Escon connections. The two-node configuration connects up to 512 tape drives, and the four-node system connects up to 1,024 drives. Pricing starts at $110,000 for the two-node Escon system.

The MAS system supports one or two Ficon or Escon connections and up to 526 drives.

The MDL and MAS support Fibre Channel, IP, or SCSI connectivity to connect IBM zSeries or Unisys OS2200 mainframes to EMC Centera or Celerra or Network Appliance NearStore systems. (See Bus-Tech Supports EMC and EMC Broadens Centera Support.) It's that support for lower-end storage systems that sets Bus-Tech apart by saving its customers from having to back up to enterprise systems such as EMC's Symmetrix or IBM Shark.Bus-Tech director of product marketing Jim O'Connor says the company is also working on MDL certification for Hitachi Data Systems' content archiving platform. (See Hitachi Picks Archiving Partner.)

O'Connor says Bus-Tech decided to scale up because its reseller deal with EMC brought it into larger shops than originally anticipated. He says Bus-Tech's 250 or so customers use mainframe VTL for disaster recovery and to speed up backups - the same reason they turn to open systems VTLs.

Seattle-based Grange Insurance is on the small side for a mainframe shop with about 250 employees. Systems programmer Dale Caldwell says his firm uses two MAS appliances to back up and restore mission-critical data from an IBM mainframe onto a Dell PowerVault NAS. Grange has one MAS in its headquarters and another in a DR site in Spokane.

"Our initial plan was not so much disaster recovery but to get away from physical tape cartridges," he says. "I wanted an automated system. We had a DR site in place, using Double Take software to replicate between here and there for client server. I thought, 'Couldn't we do the same thing with tape?'"

Caldwell says he used to back up twice a week and ship the tape cartridges offsite. Now he can do nightly backups to a remote site quicker and without handling tape. And where the backups often run over until the office opened in the morning, the virtual tape backups are usually completed by 5 a.m.There are advantages and disadvantages to using appliances such as Bus-Tech's. The Clipper Group analyst Diane McAdam says the integrated VTLs from IBM and Sun include VTL software with their mainframe tape libraries and can make the process easier, but they cost substantially more than Bus-Tech. Software-based VTLs cost less but use CPU cycles and render slow performance.

"Sun and IBM give you the complete package, the virtual tape and libraries," McAdam says. "You can set policies that say after data has been sitting around a certain amount of time, write it off to tape, and it does it automatically. You can argue IBM or Sun has tighter integration, but you don't have as much flexibility. You can't say 'I'm going to put IBM in front of StorageTek's silos.'"

McAdam says because Bus-Tech's MDL uses the snapshot capability built into EMC or Network Appliance products to take snaps of logical tape volumes, it makes it easier to test DR plans.

"The problem with disaster recovery is it's hard to test," she says. "You usually have to bring down the system. Bus-Tech lets you test your DR scheme live because they use other people's disk drives that already have the function built in. When testing is done, you delete the snaps and go back to normal."

Caldwell says he's used Bus-Tech's library for exactly that purpose. "We've run DR tests, and they've gone smoothly," he says. "I'd write a tape to virtual storage here, replicate it, and do a byte-by-byte comparison."Bus-Tech lags behind its competitors with built-in encryption, but O'Connor says that will be available for the MDL by the end of the year. (See CA Makes Mainframe Security Play.) Bus-Tech supports NeoScale's encryption devices but does not encrypt data natively.

— Dave Raffo, News Editor, Byte and Switch