no no no ... there is no need to detach any mirror DO NOT DETACH ANY MIRROR AND DO NOT DO ANY METACLEAR

Configure your /etc/vfstab file to first boot up in block device, hash off those entries in /etc/system then reboot server. until you are sure the server can boot up properly in block device then only do metaclear.

This is because in the event some thing screw up you can still fall back, if something bad happens just
cp /etc/vfstab.ORG.APRIL /etc/vfstab
cp /etc/system.ORG.APRIL /etc/system

I don't want to lecture you but when you do something like this you must ALWAYS think where is your way out, what is the fall back plan in case something goes wrong, don't do something without any planning then when things go wrong and you start to regret, it will be too late by then.