News

posted on 25 February 2008 17:18

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EMC has upgraded its CLARiiON-based Disk Library virtual tape line to add the DLm, which supports mainframes. Unlike existing Sun and Fujitsu Siemens Computers virtual tape library (VTL) products it has no tape back end.

The EMC DLm (Disk Library for mainframes) employs 1TB SATA drives and connects to mainframes by either FICON or ESCON channels. It presents itself to the mainframe as an IBM tape drive, offering integration with existing backup procedures and processes but at disk speed. There are two configurations:; one with two virtual tape emulators and another with four. THe DLM disks are protected against two drive failures as RAID 6 is offered.

It offers up to 500TB of compressed data capacity and 600MB/sec of throughput. EMC says this is 33 percent more than competing mainframe VTLS, understood to refer to Sun's VSM v5 and FSC's CentricStor Virtual Tape Appliance v4.

VSM offers up to 256 virtual drives, FICON connectivity, up to 28TB of disk storage and the ability to group boxes together.

The FSC product offers up to 1PB of disk capacity, thin provisioning, clustered nodes for scalability and reliability, and supports FICON and 4GBit/s Fibre Channel connectivity. De-duplication of its stored data is expected to be added later this year.

Both the Sun and FSC mainframe VTLS are integrated with back-end tape libraries which offer vast data storage capacities. EMC has eschewed this, offering a tapeless product. The FSC product has a disk-only, tapeless capability. Sun's VSM does not.

EMC says its DLm product provides asynchronous replication of stored data over an IP network. However there is no mention of de-duplication, which can radically reduce the space taken up by stored backup data through eliminating redundant files and parts of files. Nor is there any mention of thin provisioning which can delay disk capacity purchases until they are actually needed for data writing, instead of being needed initially for logical allocation reasons.

This looks like an EMC toe-in-the-water and emphasises the company's intention to be an across-the-board disk storage supplier. EMC's DLm will be available in March. No pricing information was supplied.

(EMC Dl4100 disk library pictured above.)