Re: Save While Active Question -- MIDRANGE-L

Questions like this are when we really miss Al Barsa....

Here's my take:

Save While Active (SWA) offers 3 options
1) Hard
2) Easy
3) Ragged

Option 1) Hard provides for 100% uptime, but requires the use of
journallying and commitment control and the backup/recovery is so
difficult nobody uses it. A HA system is easier.

Option 2) Easy involves shutting down, or quiescing, the system
bringing it back up after the checkpoint has been reached.

Option 3) Ragged, which was added at v5r3, provides for faster
checkpointing than option 2, but requires journalling and commitment
control and involves a more complicated recovery than option 2.

One thing to keep in mind, with option 2 & 3 you can reduce the time
it takes to reach a checkpoint by reducing the # of objects that need
to be checkpointed. For example, if you save 10 libraries, but only
one has objects in use, do a SWA on the one and a regular save on the
others. Ideally, you'd move all the active objects to a single
library. In you're case, those 10-12 files you mention would ideally
be in a library by themselves.

Lastly, while both the easy and the ragged recommend quiescing the
system, you can do SWA without shutting down the application as long
as there's an opportunity for the system to do the checkpoint. For
example, lets say the only activity is a batch process that runs
continually in a loop with a DLYJOB before restarting. The DLYJOB
might be enough time for the checkpointing to occur. Or for example,
you've only got a few users on the system, it's likely the system can
get the checkpointing done during the users "think time".

When you have lots or users, or lots of processes that you can't
control, then quiescing the system is often the only way to go.

HTH,
Charles

On Mon, Apr 20, 2009 at 8:16 AM, John Candidi
<jacandidi@xxxxxxxxxxxxxxxxx> wrote:

John A. Candidi
American European Insurance Group
AS400 & POINT Application Manager
856-779-2274
jacandidi@xxxxxxxxxxxxxxxxx<mailto:jacandidi@xxxxxxxxxxxxxxxxx>

-----Original Message-----
From: John Candidi
Sent: Monday, April 20, 2009 8:01 AM
To: 'midrange-l-owner@xxxxxxxxxxxx'
Subject: Save While Active Question

We have about 20 libraries we save every night to a 3580 tape drive. 2 of them have quite a few objects. We are being asked to allow some form of processing each night while the save is going on so I wanted to use the save while active option? Currently, the backup takes only about 45 minutes. In anybody's experience, will this increase the time it takes to run the backup or cause any other problems in your experience? It really all boils down to the potential that 10-12 files may open from ONE of the libraries at some point during the save. The system is not in a restricted state while doing this save since they are all basically user libraries.

John A. Candidi
American European Insurance Group
AS400 & POINT Application Manager
856-779-2274
jacandidi@xxxxxxxxxxxxxxxxx<mailto:jacandidi@xxxxxxxxxxxxxxxxx>

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