Last week we looked at Acopia. It offers a NAS performance and performance capability through its proprietary hardware and software ARX appliance. There are other suppliers who offer NAS acceleration and growth functionality. BlueArc is one and Exanet, Isilon and Montilio are recent additional entrants to this market. How do they do what they do, and how do they compare?

BlueArc is probably the longest-established NAS performance and capacity growth improving supplier here. Its performance has regularly broken SPECsfs records. In March this year its Titan 2200 Storage System achieved SPECsfs97_R1.v3 benchmark results that doubled the company's world record for single and dual node system performance at 98,131 operations/sec (ops).

This number also far exceeded that of any network storage solution on the market, utilizing a single namespace. Titan 2200 dual server performance was 195,502 ops.

BlueArc's first-generation Titan storage system achieved 50,858 SPECsfs ops in November, 2004, and held the SPECSfs single server record until March this year when the same company's Titan 2200 near enough doubled it.

The 2200 used Engenio Fibre Channel and serial ATA (SATA) drives. Titan consists of NAS nodes that can be clustered together as pairs for scalability and availability. It can provide up to 512TB capacity in a single cluster namespace with a unified directory structure and CIFS or NFS client access via any node in the cluster.

Nodes have a proprietary hardware architecture and BlueArc software. This software offers the NAS and cluster functionality plus data migration, non-intrusive back-up and replication, and anti-virus support. Storage can be tiered with FC, SATA and WORM (write-once, read many) storage tiers.

The file system virtualises the NAS capacity into virtual volumes or logically separate NAS resources.

Recent customer wins include media companies and life-sciences organisations. A simplistic categorisation of BlueArc's product is as a self-contained total go-very-much-faster NAS system (NAS gateway plus network cards and drive arrays) and obtains its performance by building proprietary systems from tuned hardware and software (using techniques such as parallel RAID striping). For cost comparison purposes think $100,000 for 8TB of storage.

This company produces a clustered NAS system which was initially described in Techworld here. Access protocols supported include Apple's File Protocol (AFP) as well as CIFS and NFS.

Exanet ExaStore software is currently at version 2.2. It runs on Intel industry-standard hardware and independently scales capacity, performance and I/O. The basic product consists of two clustered nodes with the ExaStore software and ExaFS file system. Behind the Intel-based nodes are the RAID drive arrays - so this is a NAS gateway approach with proprietary software running on industry-standard hardware.

Exanet claims it can scale up to a 1EB (exabyte) capacity system; that's one thousand petabytes, meaning one billion terabytes meaning a very large number of gigabytes indeed. You do this by adding nodes and arrays. All the arrays are virtualised into the single namespace provided by ExaFS.

The clustered pairs form high availability nodes. Both data and file system metadata are fully distributed throughout the system for performance reasons; there is no metadata bottleneck as there might be if a single resource handled the metadata. It looks like a grid-based NAS system.

This ExaStore 2.0 software in a 6-node EX600FC clustered network-attached storage (NAS) set-up reached a record-breaking SPECsfs performance of 203,182ops with an overall response time of 1.08 milliseconds.

Version 3 of the software, due in the summer period, will add full continuous data protection (CDP) support and include snapshot and module management functionality.

Rami Schwartz, Exanet's CEO, says that there are customers in several vertical markets but the application is horizontal. Organisations in post-production, telcos, healthcare and media companies, for example, all face a need to distribute millions of files to customers or user devices, such as telephone handsets, which is what one telco customer does with around 100 million distributable files. What Exanet does: "is provide a means of running a horizontal application very well. The content is what makes the demand, not the vertical market sector. It's rich content. Sometimes it's small files; sometimes files, such as images, that are very big. They all need performance and scalability."

Exanet has fifty customers with production systems in the 20-30TB capacity area. Customers have very much larger systems; one has a 130TB system. In fact one customer started with zero (Exanet) TB one year ago and now has 100 (Exanet) TB.

Here we have another self-contained NAS system, a BlueArc-like approach but software only and running on standard hardware. It can scale in performance more then twice as much as BlueArc and should cost less too. Schwartz indicates that the customer sweet spot is in the 30-60TB NAS capacity area.

What you might consider as a starting categorisation is to look at BlueArc if you want a single clustered node to perform very well and scale up to half a petabyte. Look at Exanet if you are concerned about lower costs and/or need to provide for overall performance past a BlueArc cluster limit

Part two of this feature will look at Isilon and Montilio. It will appear on June 1st. A third part will appear on June 5th and look at NeoPath, Brocade's NuView (StorageX) and OnStor.