Re: Power HA and Journaling.

Oh yes! Suppose in your environment the primary system goes away. You now bring up the iASP on the remote system and without journaling you get access paths and other PF issues resulting in damaged objects. Simplest way to find them: Do a save!

- Larry "DrFranken" Bolhuis

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

On 1/30/2015 12:36 PM, Stefan Tageson wrote:

Hi Jim,

Could be a misunderstanding from my part - sorry if so - but I've never seen a damaged object due to transactions not being written from the journal cache.
Lost transactions - yes- but damaged objects - no. Do you have a different experience?

Best regards

stefan.tageson@xxxxxxxx
M +46 732 369934

-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Jim Oberholtzer
Sent: den 30 januari 2015 18:31
To: 'Midrange Systems Technical Discussion'
Subject: 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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