Thanks Rob, that was my feeling.
John A. Candidi
American European Insurance Group
AS400 & POINT Application Manager
856-779-2274
jacandidi@xxxxxxxxxxxxxxxxx
-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of rob@xxxxxxxxx
Sent: Monday, April 20, 2009 2:42 PM
To: Midrange Systems Technical Discussion
Subject: RE: Save While Active Question
If you use *SYSDFN then you can do this. However you need to be aware of
some facts. The first and foremost is that data will not be in sync on
your save. For example, if your transaction writes out to both the
ORDHEAD and ORDLINE your save may have the update on the ORDHEAD but not
the update on ORDLINE. You are not using a "checkpoint". This can make
your restores much more confusing, or you can cross your fingers and trust
to luck. Here, they adopted the "cross your fingers and trust to luck"
despite my objections.
Send the email with a bcc to yourself. Keep the reply saying they are
aware of the risks but do it anyway. Print them, take the copies home.
Forget about it.
Sample transaction.
Was:
ORDHEAD
OrderNumber = 1
WeightOfOrder = 100
ORDLINE
OrderNumber = 1
OrderLine = 1
WeightLine = 75
OrderNumber = 1
OrderLine = 2
WeightLine = 25
Update occurs. Added line 3 of 15 weight.
Write out new line.
Save occurs.
Write out updated header.
Disaster occurs.
Restore data. Now have
ORDHEAD
OrderNumber = 1
WeightOfOrder = 100
ORDLINE
OrderNumber = 1
OrderLine = 1
WeightLine = 75
OrderNumber = 1
OrderLine = 2
WeightLine = 25
OrderLine = 3
WeightLine = 15
Notice how the weights do not add up? 75 + 25 + 15 <>100
Rob Berendt
--
Group Dekko Services, LLC
Dept 01.073
Dock 108
6928N 400E
Kendallville, IN 46755
http://www.dekko.com
From:
John Candidi <jacandidi@xxxxxxxxxxxxxxxxx>
To:
"'Midrange Systems Technical Discussion'" <midrange-l@xxxxxxxxxxxx>
Date:
04/20/2009 09:36 AM
Subject:
RE: Save While Active Question
Sent by:
midrange-l-bounces@xxxxxxxxxxxx
Thanks Evan. Let me be clearer. The processing I was talking about was
user input into some of the files while the save is running. The idea is
to not shut them out completely while running the save
John A. Candidi
American European Insurance Group
AS400 & POINT Application Manager
856-779-2274
jacandidi@xxxxxxxxxxxxxxxxx
-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx [
mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Evan Harris
Sent: Monday, April 20, 2009 9:15 AM
To: 'Midrange Systems Technical Discussion'
Subject: RE: Save While Active Question
Hi John
My experience has been pretty good with save while active, although you
need
to take care how you save your libraries to ensure your save has some
internal consistency and integrity across library boundaries.
Basically in your situation what I would shoot for is to shutdown all
activity as you are already doing, and then start the save while active on
the required libraries, specifying a save while active message queue.
In the backup program, just before the actual save process is initiated,
submit a job that reads messages from this message queue. When the save
while active checkpoint is reached a message arrives on the message queue
signaling that you can safely re-start your production processes and let
the
save continue on in the background.
The backup itself will take longer but you will reach the checkpoint much,
much quicker; since the system is available the additional backup time is
not such an issue. Obviously there may be also a performance penalty on
your
production jobs.
Some things like save files can cause problems, for instance if you are
saving to a save file that's being saved, but I have not seen any other
major issues providing the save is set up correctly.
If you need more detail feel free to ask.
Regards
Evan Harris
-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of John Candidi
Sent: Tuesday, 21 April 2009 12:17 a.m.
To: midrange-l@xxxxxxxxxxxx
Subject: Save While Active Question
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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