Expansion potential is extremely good as limitations are based on the drive count rather than the number of shelves. Each controller has an embedded 36-port SAS expander linked to its expansion port so a pair of controllers supports up to 96 hard disks. You can daisy-chain as many shelves as you like as long as you don't go over this number of drives.
You can mix and match IBM's EXP3512 and EXP3524 expansion shelves, join them with multiple redundant SAS paths and have different SAS drive types within the same shelf. The controllers have 1GB of cache but the battery backup plays a different role than usual. In the event of a power failure it keeps the controller running so cache contents can be de-staged to an on-board 8GB SD memory card.
Deployment in the lab was simple enough as the DS3512 is managed with IBM's Storage Manager 10 Client (SMC10) utility. This kicks off with a discovery routine that searches the network for storage arrays and displays them ready for configuration using a variety of wizards.
Your first job is to create RAID arrays and SMC10 offers plenty of advice and assistance on the best choices. It also checks all the physical drives and lists them based on capacity, interface and spindle speeds for easier identification. You can take manual control where you select an array type, choose the member drives and decide whether to set any aside for hot-standby duties. SMC10 validates your choices and then offers to carve the storage space up into equal sized logical drives or lets you create them yourself.
Logical drives are then mapped to hosts and SMC10 automatically identified our test servers connected to the controller via 8Gbps Brocade FC HBAs. During this phase you can decide whether a host has dedicated access to a logical drive or shares the mapping with others.
