Product Reviews

IP SANs have rocketed in popularity among SMBs over the past year, and you just know iSCSI has come of age when Hitachi Data Systems (HDS) wants a piece of the action. In this exclusive review we take a closer look at its latest Simple Modular Storage (SMS) solution, which aims to deliver affordable network storage to smaller businesses. And it succeeds too.

It helps that the SMS 100 is no ordinary storage appliance. Although the system supports up to 12 hard disks, a peek behind the front panel shows they aren't accessible to users. The chassis has 12 drive bays at the front and removable covers, so-called 'repair bays', are positioned on each side for two drives only. That's leaves ten slots at the front but HDS has secreted two more drives in separate bays underneath the lid.

The SMS 100 supports both SAS and SATA hard disks, with HDS offering three configurations where you can have six, eight or 12 drives fitted. HDS is also playing the green card, describing the SMS 100 as "power-efficient", but take this with a pinch of salt: with only six drives installed our in-line power meter showed the appliance pulling nearly 300W when under load.

All drives are preconfigured only as a RAID6 array, which provides dual drive redundancy. Essentially, if one fails, the appliance notifies you by email, you order a new one - which you slot into a free repair bay and leave the appliance to rebuild the array. If another one goes down you carry out the same procedure using the remaining bay. Users aren't required to touch the failed drives, which are left in situ.

In the unlikely event of another drive failure HDS sends out a complete new appliance. The RAID controllers have an 'auto-migration' SAS port at the rear, which you connect to the new unit using the supplied cable kit and initiate a copy of all data from the degraded unit. The primary unit isn't taken offline until the copy has finished and you then promote the new system to primary status and ship the old one back to HDS. This even applies to power as the appliance is completely replaced if one supply fails.

The RAID controllers aren't user replaceable either. On review is the dual controller model where both function

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in active-active mode, providing a good range of fault-tolerant connection options. Each controller has a pair of gigabit data ports along with a separate management port. These mustn't all be on the same physical network otherwise the management ports can't be accessed.

For installation and configuration HDS has modified its enterprise Storage Navigator Modular (SNM) management software, allowing it to look after multiple SMS 100 appliances. SNM2 runs a group of services on a designated host system and its web services can be accessed either locally or from another remote system. Don't change your mind after installing the host system services as the uninstall routine doesn't work properly and we found we couldn't get rid of SNM2 without doing a complete OS refresh.

SNM2 offers a very well designed interface which opens with links to a quick setup routine and common tasks, including logical unit (LU) creation and volume backup. iSCSI target presentation is handled neatly as you create an LU, decide on its size in MB, GB, TB or blocks and choose a LUN and stripe size. You can assign it to a specific data port and either use an existing iSCSI target or create a new one.

Enabling security on individual data ports stops more than one host logging onto an iSCSI target, and you can implement CHAP authentication as well. The LUN expansion feature allows you to select a primary LU and combine other LUs with it to create a single larger one. The process is simple enough to use and we liked the option to reverse the process. Optional features comprise a volume backup tool, Copy-On-Write snapshots, ShadowImage replication and TrueCopy Extended Distance software - the latter is used to replicate data across SMS 100 appliances at different sites

The SMS 100 delivered for speed. For testing, we used a pair of Boston Supermicro dual 3GHz Xeon 5160 servers loaded with Windows Server 2003 R2 and Microsoft's iSCSI initiator. With one server logged into a data port on one controller we saw Iometer return a speedy raw read rate of 110MB/sec. We logged the second server onto a dedicated data port on the other controller and watched Iometer report a cumulative throughput of 218MB/sec for both systems. Single controller appliances won't see such high speeds as logging the servers onto the data ports on one controller saw Iometer return a cumulative 109MB/sec.

The SMS 100 is unique, as it's designed to keep user intervention to an absolute minimum in the event of a hardware failure. Just bear in mind that RAID6 is quite hungry for capacity resources - in a six-drive array you'll lose two for parity operations. Nevertheless, HDS is offering a very competitively priced IP SAN solution that's packed with features and masses of redundancy and has a good turn of speed as well.