3PAR thins storage arrays

Revs its ASIC to slim down fat volumes


Today 3PAR is doing its bit to solve the storage obesity problem with new T-class InServ storage servers featuring a third-generation ASIC and hardware-assisted fat-to-thin volume transformation.

Currently 3PAR offers two S-class storage servers, the S400 scaling to 300TB with Fibre Channel SATA drives and S800 scaling to 600TB with the same drives. A storage server is composed of two or more controller nodes with drive arrays. The controller nodes are clustered - interconnected - by a full mesh passive backplane which operates at 1GB/sec and connects to an ASIC in each node. The S400 can have 2 to 4 controller nodes, the S800 2 to 8.

There is also an entry-level E200 system scaling to 96TB with just 2 controller nodes. All products have the same operating system and firmware. The S400 and S800 were launched in 2004 and have had in-model upgrades since then with larger capacity FC and SATA drives and a second generation ASIC.

The new machines are effectively the old ones with a storage ASIC brain implant plus a coming operating system revision. There is no change in the backplane design, port counts or hard drive types and numbers. Like the existing S400 the T400 has 64 Fibre Channel (FC) ports plus GigE and iSCSI support, and scales up to 640 drives. The larger T800 has 128 FC ports and can have up to 1,280 hard drives just like the S800.

An SPC-1 benchmark, the fastest single system one, for the T800 has been submitted and it shows 245,989,65 SPC-1 IOPS at $9.30 per IOPS. No short-stroking of drives was needed for this and the array was 83 percent capacity utilised. For comparison a high-end HP XP24000 recorded 200,245.73 SPC-1 IOPS at a cost of $17.96/IOPS. The S800 had an May, 2004 SPC-1 rating less than half that of the T800.

The new ASIC has new 'zero-detection capabilities' which help a storage volume become, and stay, thinly provisioned.

Thin provisioning means an application 'thinks' it has, say 20TB of capacity available, into which it has written, say, 5TB of data. In fact only 5TB plus a margin is allocated to it with the array controller allocating more storage as it is needed for writing data. This avoids having a lot of pre-allocated but unused disk space in an array.

Zero-detection means that an existing storage volume, perhaps migrated to the new systems, can be checked by the hardware and allocated but unwritten capacity - full of zeroes - detected and reclaimed in a fat-to-thin volume conversion. This zero-detection silicon is separate from the controller CPU and RAM resources so that ongoing storage operations are not affected by the fat-to-thin conversion process. 3PAR says a software-based fat-to-thin process would have used up controller CPU and RAM resources diminishing service levels for users. However this special hardware will only be enabled by a coming release of the InForm O/S for the new systems.

The new ASICS also run data movement in parallel with the metadata processing performed on the Intel CPU-driven controller nodes. They support an accelerated RAID 5 implementation with a built-in RAID 5 XOR engine. Apparently it delivers performance levels comparable to RAID 1 without the overhead.

3PAR says the new products will enable it to strengthen its message of massive scalability within one system making it more attractive to cloud storage and storage-as-a-service applications, which are becoming a core customer area for its machines.

An entry-level T400 with 2 controllers, and 16 147GB FC drives will cost about $130,000. In general there is a small premium over the effectively replaced S-class products.

It is known that the IBM XIV marketing people think that 3PAR is their main competitive focus in cloud SaaS applications. These new T400 and T800 models will increase the pressure on IBM's XIV developers to come up with the product delivery goods and quickly release an upgraded system.


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