RE: How to perform a GIG MIG

When we've replaced all the disks at once, we essentially did the
backup-replace drives-restore routine.  Everything I've heard says that
a re-load not only distributes your data in the most efficient manner,
but will be faster than removing disks from the config.  You also end up
with a known good system save or two.  Our process is:

1. Make 2 GO SAVE/21s (I guess we're paranoid).  We clean the tape drive
before the first save and use new tapes only.
2. Remove any optical media from the CD drives.
3. Power down & remove all disks being replaced.  Note that (at least on
7xx and newer) you should't need to note the exact location the old
drives were in.  They only need to be attached to the same controller
card; the exact disk slot doesn't matter beyond that.
3. Install the new drives & IPL from D (alternate load source).  This is
why we remove any optical media: When IPLing from D the system might see
& attempt to IPL off a CD disk before it sees the tape drive.  While
harmess (unless you happen to have the LIC CD loaded), it'll add time to
your IPL).
4. Perform the restore as detailed in the Backup & Recovery manual.
It's procedures will guide you through building the RAID set(s), adding
disks to the ASP, and the restore itself.

Really, all of this, including disk replacement, is in the Backup &
Recovery manual.  Truly the most helpful IBM manual I've ever used.  For
this scenario, I typically will make my saves and then follow the "load
source failed, no RAID enabled" checklist which assumes the load source
has failed and, since no RAID was enabled, the system has to be restored
from backup.

The only downside to most shops is the loss of spool files.  In our shop
reports are converted to PDFs in the IFS so we don't consider SPLFs to
be of value.  If it is an issue for you, you can acquire one of the
inexpensive SPLF save applications.  Or, if you've access to another
box, RMTOUTQ all the SPLFs to that machine, do the upgrade, RMTOUTQ them
back.

I've done this 4 or 5 times over the past few years and have never had a
problem.

John A. Jones, CISSP
Americas Information Security Officer
Jones Lang LaSalle, Inc.
V: +1-630-455-2787  F: +1-312-601-1782
john.jones@xxxxxxxxxx

-----Original Message-----
From: William A.(Tony) Corbett [mailto:corbett@xxxxxxxxxxxxxxx] 
Sent: Tuesday, November 16, 2004 8:10 PM
To: midrange-l@xxxxxxxxxxxx
Subject: Re: How to perform a GIG MIG

Steve,
I've never heard of such a thing, but you are much more likely to have a
problem trying to avoid a backup than if you just go ahead and do one.
From
my experience, a DST disk copy (the only thing I know that you could be
talking about) won't work anyway with not-exactly-the-same drives.
(been
there, etc) You're in a perfect position...you have the best backup
already,
the drives.  This takes care of the most important part of this project,
CYA.  Here's what I'd do:
1.  Do a good save-21 on a good tape drive using a good tape, if
paranoid,
do 2
2.  Mark, number, spray paint, whatever the drives so you can put them
back
in the same place.  
3.  Swap in the drives, taking real good care of the originals.
4.  reload the system from the backup, in the right order, refer to the
Backup & Recovery manual for a checklist.

If something hits the fan, well, here's where the afore-mentioned CYA
comes
in.

William A.(Tony) Corbett
IBM Certified Specialist - AS/400 Developer
http://www.asresources.com
corbett@xxxxxxxxxxxxxxx
770-587-9139 (office)
404-784-4737 (mobile)
fax:  678-935-5005


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