Brents IT Blog

Random thoughts by an IT GOAT


SAN Selection .. a process of elmination and feature set comparision

Soo we finally chose an EHR package, YAY... wait.. now i have to pick a SAN infrastructure to run it on!  Freak out.....

We currently run an old EMC Fibre Channel SAN the entire company uses for various purposes.   I have expanded it beyond what we originally paid for and i personally think its life is coming to an end over the next year.  So i decided that i would base part of my decision for buying a SAN to run the EHR software, i would ensure we could also move the rest of our systems later.  This required the SAN technology to be easily expanded and quickly able to handle a large load.

After much deliberation and price checking, the decision came down to two SAN manufacturers, Lefthand and Equalogic.  While we liked the EMC SAN, it had some limitations and i wanted to make sure our new system did not have the same issues.  I also wanted an easily expandable system that was fully robust.  The system must be widely supported and have excellent redundancy for the price range.

Equalogic was being used a by many companies, dell just recently purchased them and the lefthand guys were tossing them under the bus as much as they were tossing lefthand under the bus.  Equalogic offered easy expandability within the same controller hardware but not much expansion past the disk system.  They primarily focused on disk systems and thats fine.

Lefthand was not as widely known, though they seemed to have offered the most robust product i have seen.  While it was initially more expensive than an equalogic(we negotiated this down), you could literally add another box and mirror the two(or three or four on up).  Even though you had to add another box, you gained additional controllers, more disks, more network cards and even more redundancy.  I didn't like the fact that each system came as one server and in order to add capacity, you had to add another server, but from a bottleneck perspective, the more hardware the merrier.  Obviously, its important to plan your storage needs ahead of time, but the more hardware, the better shape you are in.

As you have probably gathered by now, we decided on the Lefthand SANs.  We bought three units and clustered them in a 2 Way replicated environment.  While this meant a large amount of space was wasted on redundancy, Medical Records demand this type of online backup.  Doctors also demand high up time, so having no single point of failure(each box has redundancy built in), uptime was also a major factor.  Also, as noted above, the addition or more hardware prevented most bottlenecks from even hitting the radar unless a LUN is horribly configured.

We bought these units for the sole purpose of storing data on them and running VM's from them.  So far so good!