Re: Logon during night backup on tape

Zero downtime is possible, as long as they don't mind spending some $$$ to
get it.

Concur. For reasons unknown to me, when you ask for a tool or solution for
the IBM i the answer is, generally, "roll your own". The Windows people get
to buy theirs :-( . Maybe is all that marketing about "the system is
integrated, it has everything", etc.

Regards,


Luis Rodriguez
IBM Certified Systems Expert — eServer i5 iSeries


On Fri, Nov 13, 2009 at 11:04 AM, <daparnin@xxxxxxxxxxxxxx> wrote:

Zero downtime is possible, as long as they don't mind spending some $$$ to
get it. Even then, you should know where you were at with the "moving
target" when you did capture the backup. If management has an incorrect
perception then they need some education to get their expectations in line
with reality (easier said than done).


Dave Parnin
--
Nishikawa Standard Company
Topeka, IN 46571
daparnin@xxxxxxxxxxxxxx





Luis Rodriguez <luisro58@xxxxxxxxx>
Sent by: midrange-l-bounces@xxxxxxxxxxxx
11/13/2009 09:59 AM
Please respond to
Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>


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Subject
Re: Logon during night backup on tape






Dave,

As soon as people (and, sometimes, IT managers too!) hear the phrase
"save-while-active" they insist on zero downtime. We had that problem in
our
shop. The managers told us that the iSeries could not be stopped (even for
30 min.). Strangely enough, now that they use Windows/Unix for the core
apps, they don't see the problem of getting the servers out of service for
backup reasons.

Go figure.


Regards,

Luis Rodriguez
IBM Certified Systems Expert — eServer i5 iSeries



On Fri, Nov 13, 2009 at 9:38 AM, <daparnin@xxxxxxxxxxxxxx> wrote:

The major problem with "Save-While-Active" is ensuring that the
transactions are synchronized during the backup. For example, suppose
you have a program that saves a particular transaction in three
different files (and records). It could happen that your backup saves
FILE1 sans RECORD1 and, after that, your app runs and writes the three
records. A short time later, your backup saves FILE2 and FILE3. At
that moment, your backup data is inconsistent.

Save-while-active is the way to go. Synching isn't a problem if you
approach the shutdown properly. If you temporarily end QINTER and

quiesce

subsystems that might have jobs with record locks it's pretty
straightforward. We went from having the system down for about 2.5

hours

to about 20 minutes. (That was on our old 720.) Ending jobs and

shutting

things down is the hardest part. Once that's done you can have a job

that

sits in its own job queue monitoring a message queue waiting for the
message that the checkpoint has been established. After that, you can
resume normal operations. If you try to start a SWA in an uncontrolled
manner then you probably will have issues. It's too bad that Al Barsa
isn't around to campaign for save-while-active. He really helped me

with

it.

Having said that, we now have zero downtime. We just end mirroring to

our

DR-system and do the backup on it.


Dave Parnin
--
Nishikawa Standard Company
Topeka, IN 46571
daparnin@xxxxxxxxxxxxxx
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