IQ storage too good for SAN and NAS

On Monday [23 July] Isilon announced a 50% capacity upgrade for its IQ series clustered storage systems, through 750 GB SATA disks replacing 500 GB, along with some software additions.

Hardware upgrades are common of course, but more interesting to me is that Isilon’s success to date has been achieved with the company having nothing to do with either SAN or NAS. The reason is simple. The unique IQ architecture could not achieve its lightning throughput performance and huge file-size capabilities if shackled inside a SAN or NAS.

This begs the question: why do most enterprises unthinkingly go for SAN and NAS nowadays? It is, of course, a matter of what you are doing. However, it may be that the capabilities of an IQ-type clustered architecture needs to be better appreciated beyond the specialist markets where Isilon is focused.

So I think it is worth dwelling for a moment on how Isilon puts it all together.

The IQ series is modular with up to 96 2U height ‘nodes’. Each node now consists of up to 18TB of SATA disk storage (giving total capacity well into petabyte territory), as well as 1GB cache memory and a CPU. The channel switched connection between them uses a Gigabit Ethernet (GigE) or (preferably because faster) Infiniband (IB) backplane.

However, the key to the architecture is the OneFS internal file system. This manages and presents the total storage to the host system as though a single disk drive, and likewise aggregates the processors and memory units from each node and treats them as single raw capacity. This helps in achieving linear performance as more nodes are added so, for instance, a 10-node system has 10GB of accumulated global cache.

Unusually, the OneFS file system also has RAID along with the volume manager integrated within it. Data is written striped across the nodes with parity and checksum. This achieves higher SATA performance (since multiple read-write heads will work simultaneously to access or write data blocks). This method also achieves N+1 recovery for a 6-node system (lose one drive and you can recover using the rest), which rises to N+4 for 10 nodes and on up as more nodes are added. Incremental storage expansion occurs very simply; when you add another node it is automatically detected, so the disk begins being populated immediately and the cache memory increases the global pool.

OneFS communicates to Unix and Linux (NFS), Windows (CIFS) and Mac hosts, while Isilon’s SmartConnect software provides dynamic failover for NFS clients and load balancing capabilities.

All in all, this Isilon IQ series architecture has proven to achieve stunning throughput for markets where raw performance and/or raw capacity for very large files of unstructured data have been needed.

Now add to this that, as of Monday, Isilon’s new SmartQuotas software will allow for partitioning and quota management of the total storage pool, so it can be divided into multiple logical units with protected access. About time too some may say, but it should widen IQ’s appeal. For instance, ISPs like to share raw storage capacity flexibly between separate clients’ applications, and can now do so.

Isilon believes it has a $3.5bn market to go after without concerning itself with offering its systems for database and e-mail file support. Popular markets are: media streaming and post-production, seismic data for oil and gas exploration, life sciences, internet services, and some manufacturing, government and university applications to name a few.

With storage volumes forever increasing, the demand for this type of systems architecture must surely grow – perhaps against a flattening out of SAN and NAS sales popularity. I doubt that anyone is about to come up with SAN Mark 2 to crack the performance problem. Perhaps we be thinking a little more before rushing to buy new SANs.