Only fixes to the CP nucleus need an IPL of VM. Everything else can be done
by recycling selected virtual machines. But, then you need to know somewhat
more of VM than "PUT2PROD" (I never used it, it is too disruptive in my
eyes).
We have for example two copies of the CMS resident, so we can update CMS
while everything goes on. To place the new levels in production, we only
swap the minidisk addresses of the two residents.
e.g. MAINT 190 and MAINT 193 are the active CMS, 490 and 493 the alternates
swapping levels is simply changing the addresses of those two
minidisk sets
Users logging on after the swap use the new CMS, others continue with
the old one,
one can recycle servers one by one for those you want to use the new
level.
(it is a bit more complicated as CMS also has saved segments, we make their
name unique too)
--
Kris Buelens,
IBM Belgium, VM customer support
