I have a Raid 1 Mirror disk which is about 8 months old - put away for safty

The live Server sys vol got corrupted.... and I have been trying to get that
going again BEAST error so not holding out much hope.

No new users etc since the Mirror was made - well a half a dozoen or so
and a 2nd disk containing some old data & programes (sys 3 and sys 4) was
added a few months ago but the old mirror won;t know about it

I have a backup of Groupwise (dbcopy) and users data - copied via Rsync to a
NAS device
I can copy the user data and gw back to the OLD mirror

Can I access sys3 and sys4 - as I don't have a backup of that (might be on
old tape but would be simpler if I can just use sys3 & 4 and add to the old

How can I add the 2nd NSS disk to the old mirror ???