Hitachi Data Systems (HDS) has announced major upgrades to its two highest-end storage arrays, including software that allows the systems to mimic optical disks' WORM (write once, read many) capability. The changes are both an attempt to meet new regulatory requirements and compete with similar functionality offered by rival EMC.

HDS said the latest in its line of Thunder 9500 arrays, the Thunder 9580V, is a high-end modular storage system that can be used to consolidate smaller modular storage systems or older JBOD systems. It can also be used in a tiered storage infrastructure with HDS's monolithic Lightning 9900V array, said Hu Yoshida, the company's chief technology officer.

HDS's 9580V doubles capacity from 32TB on the old model to 64TB of SAN network-attached storage or direct-attached storage configurations. HDS also increased the number of Fibre Channel ports from four to eight running at 2Gbit/sec throughput. The array also offers up to 1,024 virtual storage ports with a technology similar to that used to create virtual private networks.

HDS also doubled the cache in its high-end monolithic array, the Lightening 9900V, from 64GB to 128GB, and increased the number of Escon ports from 36 to 48.

Most notably, analysts said, is the WORM feature added to HDS's Lightening 9900V array, a move designed to help financial service firms comply with US electronic records storage requirements.

John McArthur, an analyst with IDC, said HDS's WORM capability would compete against EMC's Centera array, which was introduced in April 2002.

"It does compete, but it doesn't do everything Centera does," he said. "Centera eliminates duplicates. There's a storage reduction capability with Centera that doesn't come with Hitachi's. If you had 17 copies of the same document in the Hitachi implementation, would it reduce that?"

The content-addressed storage software used in EMC's Centera creates a unique 27-character identifier for each document or image stored in the system. A new file with a new identifier is created each time the data is changed, so the data can't be overwritten. And each unique document can be served up to numerous users, cutting down on multiple copies of the same document.

HDS calls its technology Open LDEV Guard. It allows data to be retrieved and read by authorised persons but not altered or deleted for whatever amount of time a policy dictates.

In addition, the secure data can be replicated on-site using Hitachi ShadowImage and offsite using Hitachi TrueCopy remote replication. The data can also be replicated between Lightening 9900V arrays and Thunder 9500V arrays.

One advantage HDS may have over EMC, McArthur said, is that users will have one management platform to run both high-end arrays, including the Open LDEV Guard functions. EMC's Centera runs on its Clariion management platform, which is different from the company's higher-end Symmetrix platform.

"Both solutions will have supporters and detractors for a while," McArthur said. "Eventually, the functionality delivered on the Centera [array] is going to be enabled on general-purpose storage through some kind of application head."