RE: Power HA and Journaling.

OK, Stefan, I'll accept your reason for Journaling Performance. BUT (and a
big one) if you leave 20 damaged objects behind and have to recover them
from tape because the journaling was not written to disk in the middle of
the failure, it does not matter if you?re a bank, NSA, DOD,
companyofyourchoice, it's going to be bad. What Larry is trying to point
out is that if you use PowerHA on the IBM i side then letting plain old
journaling is the best bet.

Beside, Banks usually go for "continuous availability" not "High
Availability" . While there not much difference technically, there is a
whole pot of money difference between them.

--
Jim Oberholtzer
Chief Technical Architect
Agile Technology Architects


-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of
Stefan Tageson
Sent: Friday, January 30, 2015 10:24 AM
To: Midrange Systems Technical Discussion
Subject: RE: Power HA and Journaling.

Yep, correct, that's why I wrote "If you are not a bank".
For many of my customers the world is not black or white - and most of them
favour better performance 365 dsays/year over loosing at worst 30 seconds of
transactions ( default setting ) in the unlikely event of a system
breakdown.

Best regards

stefan.tageson@xxxxxxxx
M +46 732 369934

-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of
DrFranken
Sent: den 30 januari 2015 14:56
To: Midrange Systems Technical Discussion
Subject: Re: Power HA and Journaling.

**WARNING** **WARNING** **WARNING**

First let me say that Stefan is correct here on what option 42 does and how
it helps performance. No argument whatever..... for THAT!

BUT this thread is about PowerHA and Journaling! So think about what would
happen if you had about 160Kb of journal writes cached per arm and your
system fails. None of those writes made it to either of the DB or the
journals. (oops!) When you come up on the mirrored system you have lost all
that data! Thus option 42 would not be your best friend in this environment.

- Larry "DrFranken" Bolhuis

www.frankeni.com
www.iDevCloud.com
www.iInTheCloud.com

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