RE: RAID, journaling, and ASPs, oh my!

The problem is if you do loose the system ASP for some reason, you loose
any data since your last backup. If you have your journal receivers in a
separate ASP and it is not trashed, you can apply your journal changes
back to your restored backup, thus not loosing any data. Cannot do that
if the receivers are lost in the system ASP.


Chris Bipes
Director of I.S.
CrossCheck, Inc.

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of rob@xxxxxxxxx
Sent: Friday, February 08, 2008 12:33 PM
To: Midrange Systems Technical Discussion
Subject: RE: RAID, journaling, and ASPs, oh my!

I remember hearing this "it's better to have a separate ASP for
journals"
also.

Why, exactly, would that make a restore better? If the system ASP
dies, then do you just do a full restore, skipping all libraries in ASP2
and then ASP1 can point back to the ASP2? (Providing you've added no
drives, etc, since your last SAVSYS.)

I am reasonable sure that Jeff is going to keep using RAID. RAID should
be 4 drives or more. (Yes, if you came straight from a S/36 and you've
never seen a 4 drive raid set then you might not know that a 3 drive
raid set is a performance dog.) His journal space might only end up
taking a small percentage of a four drive set. Thus leaving a ton of
space in the second ASP. when the first ASP starts to fill then he has
to start moving stuff to the second ASP. Basically, it starts to add a
lot of management on where to place stuff. Not only that but you've cut
the number of arms serving any one particular application in half.
Our biggest lpar has 90 drives. Extensive journalling. And only the
system ASP.