CX4 I/O Modules and MirrorView

When the CX4 was released some time ago, I sat through on-line training and learnt about the differences between the CX3 and CX4. One of the big things for the CX4 was the introduction of I/O modules that enabled you to scale out front-end performance for the array. But, like any training I’ve undertaken, I filed away the information about how they work in the real world and forgot all about it.

So when we went to test MV/S connectivity between our two 960 arrays, we had some connectivity issues. When we went to establish a MirrorView connection, this is what we got on the first array.

On the second array, it looked like this.

Not so cool. But the boneheaded thing I’d forgotten from my CX4 What’s New training was that, when an array is first initialised, the MirrorView ports are assigned to the last port. If you add I/O modules after the fact, those MV ports don’t change.  So while one of the array’s was a new CX4-960, the other was an upgraded CX3-40f, which had different ports when it was upgraded. Here are some pictures that serve to illustrate my words.

You’ll notice that on the second array the MirrorView ports are A1 and B1, not A3 and B3.

And finally, it’s important to respect the zoning rules with MirrorView – something my colleague didn’t understand when he had B1 zoned to A3, and so forth. Good times.