IBM adds flash to storage virtualisation
IBM has updated its storage virtualisation product, the SAN Volume Controller, to support solid-state drives.
Scheduled for release on 6 November, SAN Volume Controller (SVC) 5.0 is the first to integrate the technology into a storage virtualisation product, IBM said. Solid-state drives have previously been available in storage arrays and as direct-attached storage.
The update uses virtualisation to manage multiple resources, including arrays from third-party vendors, as a single pool of storage. The virtualisation should also improve application availability, as it insulates host applications from changes in the physical storage infrastructure, IBM said in its announcement on Tuesday.
The controller can manage storage from multiple vendors linked over a storage-area network (SAN), including products from HP, EMC, Sun and NetApp, up to a maximum of eight petabytes.
SVC 5.0 builds on IBM's Project Quicksilver, a research project that couples flash solid-state drives with storage virtualisation. Last year, researchers reached one million read operations per second using the IOdrive, aPCIe form-factor solid-state drive from Fusion-io.
The new release of SVC exchanges the IOdrive for a 2.5-inch serial-attached SCSI (SAS) solid-state drive from Stec, called ZeusIOPS. EMC uses this drive in its Symmetrix storage arrays, which began supporting solid-state drives early last year.
With ZeusIOPS, the controller delivers up to 800,000 operations per second, with response times of about one millisecond, according to IBM. This figure is double the throughput available with the previous version of SVC.
While the Stec solid-state drive's rate is lower than the one million operations per second achieved with the IOdrive, IBM said it found the ZeusIOPS easier to service.
"There were various reasons for switching from FusionIO to Stec, the most obvious is that a hot-pluggable drive is much easier to service than an internal PCIe adapter," wrote Barry Whyte, an engineer with IBM's Hursley-based systems and technology group, in a blog post on Tuesday.
General performance improvements with SVC 5.0 include support for 8Gbps Fibre Channel (up from 4Gbps), a tripling of the maximum cache to 24GB per engine and a faster processor, the Xeon 5500.
The product, sold in pairs of devices one rack unit high, will be priced starting at $40,000 (£24,500) per pair, without the SSDs. Each SVC will have slots to accommodate four 146GB SSDs, for a total of eight per pair.
SSDs are beginning to catch on in the enterprise. They meet a need for high-speed access to the most frequently needed data, and are cheaper than some other widely used high-speed access techniques, according to industry observers.
One such technique is the use of short-stroked hard-disk drives (HDDs), which use only a fraction of the available disk space in exchange for faster throughput. SSDs can provide better throughput at a lower price than banks of such HDDs, according to Jim Handy, director of research firm Objective Analysis.
"Although the price-per-gigabyte for SSDs is prohibitive in comparison to HDDs, there are certain cases in which SSDs save money over their HDD counterparts," Handy wrote in a report published this month. "In many cases, a single SSD can provide more speed than a bank of enterprise HDDs at an adequate capacity for a reasonable price."
He noted that a number of vendors now sell SSD arrays. These include Sun, which introduced a flash-based storage array with a capacity of up to 2TB on 12 October.