The problem:
Linux guest (OpenSuse 12.1), with multiple virtual disks attached.
3 disks are in a logical volume, two of which are exactly 2TB.
None of the disks are independent, and due to the backup software we use, cannot be independent.
When the two 2TB virtual disks are "dependent", the snapshot fails stating that the file is too large for the datastore. When I put those two disks in independent mode, snapshots work fine (the other disk is 1.8TB).
I have therefore concluded that even shrinking the two physical disks by 100GB should solve the problem, however I am having trouble conceptualizing how to go about getting those disks smaller without breaking the LVM entirely.
The actual LV has 1.3TB free, so there is plenty of space to shrink with.
What I need to accomplish:
Deallocate 100GB from the two, 2TB virtual disks within the linux guest.
Shrink the two virtual disks by 100GB within vsphere (not as complicated).
Are there any vsphere/LVM gurus that can give me a clue?