PROD, DEV, PRODBACK, DEVBACK (not their real names) are all dedicated
lpars. No host/guest for those.
Some Domino lpars are guested.
However, whether or not they are hosted or not is irrelevant. Sure, if
PROD was guested under HOST and HOST was taken down then I had better have
completed a Mimix switch from PROD to PRODBACK first (or my backup plan is
my resume'). While I am running on PRODBACK I could upgrade PROD or HOST
I believe SystemMirror is san with clustering available. However, you
can't upgrade the OS copy on one cluster and not on the other, right? For
example, I have a lpar called PROD. In a SystemMirror solution it's
stored on the SAN. I can access that lpar from either BOX1 or BOX2. What
I can't do is run on BOX1 on one copy of the cluster while BOX2 upgrades i
or puts a cume on i on another copy on a cluster. Something I do with
Mimix once a quarter.
Don't get me wrong, there are some nice things about SystemMirror.
Flashcopy, and the unique hardware concerns I mentioned previously. But
if a bulk of my planned outages are PTF's and OS upgrades and it doesn't
address that, then it's not a solution to my problem.