George Crump, Senior Analyst

CORAID is a client of Storage Switzerland

Holistic performance scaling means scaling everything in between the application and the storage devices. Even those individual components should scale as well. This starts with using high performance storage interface cards that go in the server. Not only should they be multi-port they should be automatically aggregating, meaning that every time you add an HBA the ports automatically join and act as if they are one. A process that is typically called port flooding, all available I/O automatically is routed to the next least busy port in a round robin fashion. With this in place if you determine that the network connection between your servers and your storage is the bottleneck then you can simply add more ports and automatically, without complex reconfiguration, get more bandwidth to storage.

That network has to be easy to scale as well. Each additional cable should not bring with it the overhead of IP to storage conversion. It also should not require sophisticated tuning and configuration. You simply provide the connectivity and the storage system should figure out the best path to access that storage. While this sounds a lot like fibre, the truth is that ATA over Ethernet (AoE) provides this kind of capability over standard Ethernet cabling.

Finally the storage itself should be able to scale but it should not require you to scale, in other words it should scale when you want it to not because it forces you to. What this means is that the scale out storage system should also be able to work as a scale up storage system as well. This allows you to use the capabilities of a single unit without having to start with buying 3 or 4 units to get started.

In fact in some environments the use of multiple standalone systems may be exactly what is desired. In these situations you can count on the operating system or virtual infrastructure to provide the services that you need plus make the management of multiple systems easy. The Coraid SRX series Ethernet SAN storage arrays fits this bill exactly. You can leverage cost effective high performance storage and let your operating environment manage the scaling.

There are times though where true virtualized scale out storage is needed. This can be a case where the performance of a single unit won't meet the demands of the application, where the number of individual storage systems becomes unwieldy or where specific storage services are needed that the operating system or hypervisor cannot provide. In this situation data should be segmented and written across the storage systems so that when a write or read request is performed multiple systems can respond to that request simultaneously. This method also reduces management in larger environments as multiple systems are interacted with as if they were one logical system. Coraid accomplishes this with their VRX virtualization appliance, which can integrate SRX systems as members into the cluster.

The important aspect of storage performance is for the vendor to take this holistic view of storage while at the same time providing the user with options. While some vendors may claim to have all these options they often provide that with disparate product offerings that are not compatible with each other. The move from scale up storage to scale out storage requires a whole new system. Very few storage system vendors take the approach of Coraid who owns the entire performance experience because they provide you with a high performance storage system and a cost effective way to connect to it while at the same time provide deployment choices without having to shift to different products whose only "integration" is that the logo matches.