EMC Corp. today launched the Disk Library for Mainframe (DLm) 8000, its first mainframe virtual tape library (VTL) that supports synchronous replication for disaster recovery and uses EMC's Symmetrix VMAX enterprise array as back-end storage.
With the DLm8000, EMC is trying to prompt its largest mainframe storage customers to move backups and archives from tape to disk. Those organizations are likely to use VMAX for their mainframe storage if they are EMC customers.
The DLm family uses the Bus-Tech gateway, which attaches to a mainframe server via FICON and does tape emulation so it appears as tape drives to the mainframe. Bus-Tech supported all storage systems, but EMC only uses the gateway with its own storage arrays.
The DLm6000 supports EMC VNX midrange storage array and Data Domain data deduplication disk target systems, the DLm2000 uses VNX storage without deduplication, and the DLm1000 is a gateway with Data Domain storage.
"The market told us there's a certain segment we weren't hitting because those customers needed more predictable recovery," said Jim O'Connor, director of product marketing for EMC's backup and recovery systems.
O'Connor said the DLm8000 is about 35% faster than the DLm6000.
Part of the speed boost comes from having a compression card inside the gateway instead of dedupe. The compression card does not take up any mainframe CPU cycles.
The DLm8000 uses the VMAX 20K model, but O'Connor said EMC will add support for its higher end VMAX 40K system.
The DLm8000 can store 1.8 PB of data on VMAX storage and customers can allocate 2,048 emulated drives. EMC claims the DLm8000 supports throughput of 2.7 GB per second. It includes 16 mainframe FICON attachments and uses EMC's z/OS Storage Manager (EzSM) software that also supports VMAX storage.
The synchronous replication comes from EMC's array-based Symemtrix Remote Data Facility (SRDF) software. Synchronous replication is needed to maintain data consistency between data in production and at recovery sites, guaranteeing that data in the data center is at the same point-in-time as data at the DR site. Unlike asynchronous replication, synchronous replication writes data to the primary and secondary sites at the same time. Asynchronous replication writes data to the primary array first and later copies that data to a replication target.
O'Connor said that makes the DLm8000 a better fit for customers in businesses with transaction-oriented processes, such as large financial institutions. He said the ability to replicate synchronously between disk libraries has the fastest possible recovery time objective (RTO) and lets customers recover data on a file-by-file basis.
"We need powerful replication, and asynch may not cover all requirements if you need data faster," he said. "So we added synchronous replication."
Silverton Consulting president Ray Lucchesi said those large customers are among the last to use tape for mainframe backup. He said EMC is trying to accelerate a move to disk in that market.
"Maybe it's taking longer, but we can see the move to disk happening there," he said of the VMAX target market. "[Tape vendors] IBM and Oracle have virtual tape systems with disk and tape. With EMC's VTL, it all goes to disk."
However, EMC isn't the only mainframe VTL vendor that supports synchronous replication. Enterprise tape vendors such as IBM and Oracle support the technology as well. Luminex also has a VTL gateway for Hitachi Data Systems, Hewlett-Packard, IBM, NetApp, Oracle and EMC Data Domain storage arrays.
The DLm8000 will be available in the fourth quarter of 2012.