Affordable storage for the SME, part one

Pricing, Continued

We wanted to calculate how much a small SAN with failover would cost. We assumed that four servers would share a dual controller SAN. We opted for a 16-port switch as we assume that additional servers will use this SAN in the future, and 16-port switches probably give the best port/price ratio. Note also that we can easily expand our 12 disk SAN with several JBODs if those servers need more disk capacity.

First, we checked out several tier one storage vendors. To keep things simple, we made an average of the prices that we encountered at Dell/EMC, IBM, and HP at the end of October 2007. The table below is not a precise calculation or a "best buy" recommendation; it is simply an estimate to give us a reasonable overview of the costs.


Several things make a typical FC SAN quite expensive. One of most important ones is the high quality, very low latency FC Switch (a Brocade Silkworm for example). Secondly, the FC HBA required for each server that gets access to the SAN is rather expensive. Other small components also quickly push the cost higher: LC optic cables are still expensive and each link between your switch and the storage rack needs a small form-factor pluggable (SFP). These compact optical transceivers are yet another cost that is usually not included in your storage rack.


The result is that for a relatively simple HA SAN configuration with less than 1.7 TB of raw storage capacity, the total cost quickly rises to $35,000 or more. It is nearly impossible to get under $20,000, even without double path HA.

Let us compare this to a SAN based on a storage appliance that leaves all options open. We tried to keep the components the same as much as possible:

• A Brocade M4400 FC Switch
• Seagate ST3146755SS 146GB SAS 15K RPM hard drive
• FC HBA: Emulex LPe1150-F4

The idea is clear: you save a lot of money if you can pick your own switch, your own hard disks, and your own HBAs. In both configurations (HA and no HA) the Promise configuration is significantly less expensive (25-30% less) than a typical tier one configuration. Of course, it may take a bit more effort to put your configuration together depending on your skill. You also need one reliable reseller who can sell you everything, so you have one point of contact if something goes wrong. Even with this stipulations, you can save quite a bit of money.

If this is still too expensive, iSCSI comes to the rescue. iSCSI appliances are not much cheaper than FC appliances; in fact, in some cases they are priced almost as high as their FC counterparts. However, the pricing of switches, cables, and HBAs is significantly lower. That allows you to build a basic SAN for less than $10000.


Intel's SSR212MC2 barebones starts at prices as low as $2500, bringing the price of a basic storage device down ~$3500. Naturally, you have to install the iSCSI software yourself. If you feel that's either too time consuming or too difficult, quite a few resellers offer complete ready-to-use iSCSI boxes based on the Intel SSR212MC2.