New Compression Tool Triples Network Storage

April 20, 2008 – 4:33 PM

Storwize has developed a new range of in-line data compression appliances which it claimed can compress files at up to 500MB/s, doubling or even tripling the effective capacity of a NAS array.

The three new systems are 64-bit, meaning they can use far more memory than the company’s previous models. That increases their performance, as the compression technology is memory-reliant, said Jon Ash, Storwize’s sales VP.

Top of the line is the STN-6800p, which has two dual-core Intel Xeon processors, plus an accelerator card with a 16-core packet processing engine. The device supports both CIFS and NFS and is designed to sit between application servers and NAS arrays, acting as a transparent front-end to the NAS, compressing and decompressing data as it is written and read.

The ability to compress files on primary storage is what sets start-up company Storwize – or Storewiz, as it used to be called – apart from the in-line data de-duplication technology offered by vendors such as Asigra, EMC/Avamar and Symantec, which is aimed at operations such as backup and replication.

The box only compresses in memory, so it has no hard drive and it never stores users’ data. It operates in-line, compressing data as it’s being written.

“In-line means zero changes to your working environment,” Ash said, claiming that it makes it more transparent to the user than Ocarina’s storage optimizer, which operates out-of-band. (Ocarina also offers an in-line reader appliance, however.)

The downside of working in-line is that the STN-6800p is therefore a potential bottleneck and single point of failure – although Storwize offers fail-over capabilities to address the latter problem.

In addition, the Storwize process inevitably adds latency into the write path – although the company points out that it may also reduce latency elsewhere, because compression should reduce the time needed to write data to disk.

“When you’re the new guy on the block, you’re always guilty until proved innocent, but in a NAS environment we are never the bottleneck,” Ash declared.

“When you get into the SAN world it’s different, but a big NAS might only peak at 100MB/s, and average 20 to 30MB/s. People are putting multiple NetApps behind one of our boxes.”

He said that the technology’s effectiveness will depend on the data it is fed – it is LZ compression, not data de-duplication, so it is only worthwhile for compressible files.

“We don’t do great on JPEGs, MP3s – that’s not our market,” he explained. “Where we do well is with documents, log files, email archives and databases. With the new Microsoft Office formats we’re still getting 50-60 percent, and with some databases we can get up to 95 percent – that’s 20:1 compression. It’s good for seismic data too.”

Another plus is that compressed files can be decompressed in software, for example if they’ve been sent to a site that doesn’t have an STN appliance.

While Storwize currently focuses on Ethernet-based NAS, it is developing similar compression technology for Fiber Channel and iSCSI storage. This week it scored US$19 million in additional venture capital – it had $8 million already – to fund its SAN plan.

Source: PC World

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