EMC AX4: The Decision

A few weeks ago, I wrote in this space about my continuing storage quest and my discovery of the newly released EMC AX4.  It seems like I've been on this search for quite some time, but, until recently, I hadn't found that "perfect" solution that met both my needs and my budget.  Until now.  At the time of my last post on the subject, I promised to report back once I learned more details.

Simply put, for the typical small or medium sized organization, the EMC AX4 should be one of the finalists in any RFP or other selection process.  As a part of my selection process, we investigated Dell (MD3000i), EqualLogic (now Dell), LeftHand and a few others.  We gathered pertinent technical information, feature sets and pricing and came down to the EMC AX4 as my final candidate.  I have previously had fantastic experience with EqualLogic, but their solution is outside the bounds of my current budget, which is rather tight at this point.

I've gathered a lot of information regarding the AX4 and determined that it's the right solution for my organization.  Here are some of the things that make the AX4 the right solution for my college:

  • Price: I'm not supposed to divulge specifics, but needless to say, the AX4 blew us away from a pricing perspective.  It's well within the means of our institution both now and over the next three years with regard to maintenance.
  • Thin provisioning: The AX4 doesn't do thin provisioning today.  However, this feature is slated for the array's first firmware update.
  • Additional licensing: Out of the box, the array has relatively limited snapshot capability - only 16 per array.  Through the addition of an inexpensive software license, this number jumps to 256.
  • Capacity: We'll be buying two AX4 units - the first unit will contain the dual controllers and will house twelve 400GB 10K RPM SAS disks.  The second unit will hang from the first and contain twelve 750GB SATA disks.  In this configuration, we'll have 13.8TB of raw capacity.  This is signficantly more than we need today, but will be necessary as we continue our foray into the world of VMware.  I should note that the AX4 does allow you to mix and match disk types within the same chassis, too.  Through the use of expansion chassis, the AX4 is expandable to 60TB (with SATA disks).  For best overall performance, the AX4 also supports 146GB 15K RPM SAS disks, but we're not using them in my organization.
  • Storage tiers: By obtaining two units--one with SAS disks and one with SATA disks--we can better control our storage and store information on the appropriate kinds of disks.  For example, our Exchange server will probably use the SAS array while our file server will use the SATA array.
  • Controller configuration: We're buying the iSCSI version of the AX4.  Each controller in the AX4 (redundant controllers) have two gigabit Ethernet ports and the two controllers work in an active/active manner.  As such, the AX4 has a total of four gigabit Ethernet links to the storage network, making storage bandwidth plentiful.
  • Multipathing: The AX4 supports EMC's multipathing software, called PowerPath.  Through this software, licenses for which are included in the array's purchase price, storage availability can be brought to higher levels.
  • Hosts: One serious limitation of the AX4's predecessor, the AX150/AX150i, was the number hosts supported - 10.  Up to 64 hosts are supported with the AX4.  This is more than enough to support the needs of my environment.

I'm still amazed that EMC has released a product that perfectly meets my organization's needs and that we can actually afford it!  I'd enjoy hearing your thoughts on the AX4 if you have one or have seen one.  There are still products out there that may have worked as well for us, but the AX4 came to the top of the list fairly quickly.

Correction made 2/28/2008 - 15K RPM disk size was incorrectly idenitifed as 300GB in size when it is actually 146GB.