VCM & Gatekeeper

Hi,

I'll try to add some info here (gotta go back into my DMX memory bank ):

1. You are correct there. The VCMDB is the LUN used in DMX arrays to store the masking repository. In the VMAX arrays this was changed to the ACLX with auto-provisioning groups, but serves pretty much the same purpose to enable communication from the host to array and be responsible for masking operations.

2. The VCM device is typically created in the BIN when the array is setup and the only interaction on it after that is to initialize it to start utilizing masking. To initialize it, the command will be a symmaskdb command - something like "symmaskdb -sid XXX init -f "

The device is a single device per array and just copied to all FA ports if enabled (VCM enabled on the FA port). There won't be multiple VCM devices in the array. This device is typically a few cylinders in size (6  or 11 cyl) or sometimes slightly larger as depicted below - but not very big at all. You can query what this device is with the symdev command and looking for the VCM noted against the device in the attribute column or if you are on a host that is zoned in-band to the array and the VCM is mapped to that FA, you can do a "sympd list vcm". This LUN us typically somewhere in the very start of the LUN addressing range of the box since it is usually created first and leveraged from the initial array setup. another command to see if it is mapped to a specific FA port would be "symcfg -sid XXX -sa -p list -address -available" - if the VCM is mapped to the FA you query, you will likely see that in this output  I believe.

If you wanted to map the device to the FA ports, you can do so with the usual "map dev to dir" command from CLI and that should work.

Hope this helps,

-Keith