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Re: Journaling without commitment control (WAS iSeries and SSD drives)



fixed

Charles,

I run into customers that do not have journaling turned on all the time, and asking if they can, so the "unlikely" part is in fact quite likely.

If journaling is causing a 50% change in the performance of a program that had not been in a journaling environment before, then there is something in the journal configuration that is causing the problem. Larry Youngren and the current batch of IBMrs that discuss journaling do it very effectively and their advise on journal and receiver configuration should be heeded.

By using the performance tools you can find where the system is waiting, and therefore adding time to a job. Most of these situations are driven by too few DASD arms, not by journaling by and of itself. SSDs help but cannot completely eliminate the need for lot's of DASD arms, and the I/O queues in IBM i that go along with them.

Jim Oberholtzer
Chief Technical Architect
Agile Technology Architects


On 1/18/2013 11:04 AM, Charles Wilt wrote:
But remember, at this point it's unlikely anybody is turning on journaling
for the first time...

So really, if you were to turn off journaling your 1hr batch job might run
in 20-30min.





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