News

posted on 19 February 2008 04:45

Utility storage supplier 3PAR has introduced single tier, SATA-only configurations of its InServe storage array where striping across multiple SATA spindles provides tier 1-like performance.

Tier 1 refers to fast Fibre Channel disks, called online in 3PAR terminology. Tier 2 or nearline refers to capacity-centric disks that typically spin more slowly and deliver less performance than a Fibre Channel drive. Other suppliers use 'nearline' to refer to automated tape libraries or optical jukeboxes but this not how 3PAR uses the term.

The company has decided to qualify, from an engineering sense, the use of SATA drives in InServe storage arrays for some I/O-intensive workloads.

Previously their use has been recommended for nearline disk storage requirements, such as disk-to-disk backup, general file storage and disk-based archiving. I/O-intensive messaging and transaction applications have had tier 1 or Fibre Channel drives recommended for them by 3PAR.

Three things have caused 3PAR to modify its position on SATA drives:-

1. They have proved as reliable as other enterprise-class drives in use. Craig Nunes, 3PAR's world-wide marketing VP, said this was true of 500GB SATA drives and so far the company's use of 750GB SATA drives was looking the same.

2. Widely striping data across SATA drive spindles means that I/O bandwidth is effectively increased raising performance far above what a single SATA drive can provide.

3. RAID rebuild time is far quicker than that for a single 750GB SATA drive. 3PAR's technology actually divides 750GB capacity into 3,000 chunklets. If a drive is lost then its used chunklets, ones with data written in them, are rebuilt using spare chunklets spread across other SATA drives in the array. This multi-spindle rebuild effort takes far less time than rebuilding a single 750GB SATA drive.

These three findings have enabled 3PAR to uprate its ideas of how SATA drives can be used. Effectively the company is saying that for non-I/O-intensive workloads a single tier of storage can cover three application types: messaging; general file storage; and disk archives.

There is also a single performance tier across these three applications. Everything runs at the same speed. This can possibly be varied by specifying different RAID levels for applications but there is no direct ability to modify the amount of striping and thus performance accruing from larger or smaller spindle counts.

SATA-only InServe arrays are more cost-effective, according to 3PAR, than InServes with a mix of Fibre Channel and SATA drives.

(Picture shows 3PAR E200 InServe aray.)