This week is EMC World, a huge event with tens of thousands of customers, partners, resellers and EMC employees talking about cloud, storage, and virtualization. EMC sells many storage solutions but most of the excitement and recent growth (per the latest EMC earnings announcement) are about scale-out storage, including EMC’s Isilon, XtremIO, and ScaleIO solutions.
As mentioned in my blog on the four big changes in storage, traditional scale-out storage connects many storage controllers together, while the new scale-out server storage links the storage on many servers. In both designs the disk or flash on all the nodes in each node is viewed and managed as one large pool of storage. Instead of having to manually partition and assign workloads to different storage systems, workloads can be either shifted seamlessly from node to node (no downtime) or distributed across the nodes.
Clients connect to (scale-out storage) or run on (scale-out server storage) different nodes but must be able to access storage on other nodes as if it were local. If I’m connecting to node A, I need rapid access to the storage on node A, B, C, D, and all the other nodes in the cluster. The system may also migrate data from one node to another, and rapidly exchange metadata or control traffic to keep track of who has which data.