e i g h t - c u b e d . c o m 

Core/Edge SAN

This morning, I spent a few hours rearranging the switches in the SAN fabrics at work. I have been meaning to do this for some time, and today was the day.

Because the SAN has grown slowly over time, it was easier to first chain switches together or create SAN "islands". About twelve months ago, I consolidated three fabrics into one large modified mesh of four switches in each fabric (there are two identical fabrics for redundancy).

With more incremental growth, it was again easier to chain switches onto the edge of the edge of the existing fabric.

Today, I fixed that. I undid the modified mesh and cabled each switch to a core switch. And the same for the two new production switches.

We now have two identical fabrics, each with a 2GB switch acting as a core switch (i.e., nothing but switches plug into it). Attached to the core we have two 2GB switches, and four 1GB switches acting as edge switches. The edge switches are where the hosts and storage plug in.

The nice thing about fully redundant configurations is that I could do all this without taking any storage or hosts off line. I love redundancy.