EXCLUSIVE: IBM System Storage DS3400 Express

IBM's storage division has been busy of late and now has a very sharp focus on the burgeoning small to medium business market. Its latest System Storage DS3400 directly targets this sector and aims to deliver an affordable and easily configured FC disk array with plenty of fault tolerance and expansion potential.

The DS3400 is a replacement for IBM's elderly TotalStorage DS400 and is based around the new Engenio 1932 Storage System which was unveiled by LSI Logic earlier this year. It brings in a number of new and welcome features as out goes SCSI to be replaced by SAS. The 2U chassis supports up to twelve hot-swap drives and can handle up to two controllers each equipped with two 4Gbps FC SFP ports and a Fast Ethernet management port. Expansion potential is looking good as the x4 SAS port on each controller is used to link up to three EXP3000 units allowing capacity to grow to over 14TB.

The Express models include either single or dual controllers along with all the necessary fibre cables and SFP modules. The review system included both controllers and prices for this start at £5,071. This doesn't include any hard disks but you can pick and choose from the full range of 15k SAS drives. Power redundancy comes as standard as all models include a pair of 515W hot-plug supplies and each controllers has 512MB of battery backed up cache which can be upgraded to 1GB for the princely sum of around £450.

The controllers can support an active/active mode where they carry out cache mirroring in this configuration. IBM also supports Microsoft's MPIO (multi-path I/O) which uses multiple hardware components to create redundant paths from hosts to storage volumes. Essentially, MPIO lets Windows see the same disk twice which allows paths from two controllers to the same logical drive to co-exist. If one controller fails the drive will be automatically reassigned to the other controller. A valuable feature here is that unlike much of the competition, IBM doesn't charge for its DSM (device specific module).

A key selling point is ease of installation and we have no problems here as we had the system out of the box and running inside an hour. The array is managed with the bundled Storage Manager 2 Client utility (SMC2) which is a rebadged version of LSI's Engenio Simplicity Manager. It's certainly easy enough to use and runs a discovery routine that searches the network for storage arrays, displays them ready for configuration and presents wizards galore. Logical drive configuration comes first where you can leave SMC2 to automatically carve up available drives into a RAID-5 array with hot-standby or you can do it manually. The latter is easy enough as you pick your drives and decide on an array type. Note that the appliance doesn't support RAID-6 but you can choose from RAID0, 1, 3, 5 and 10 and designate drives as hot-spares.

Next, you create host to logical drive mappings and we encountered a minor problem here as the task wizard was unable to automatically find our two direct attached hosts systems. It was more of an irritation than a problem as we just had to manually declare them to the appliance where we provided meaningful names and associated these with the relevant host where both our test systems were, strangely enough, being displayed in this screen. You can decide whether hosts will share access to logical drive mappings in which case they can be placed in host groups. Called partitioning, the system comes preconfigured with support for four partitions but you can license up to sixteen. Alternatively, you can restrict access and allow one host only to use a logical drive.