uvconfig shared memory settings for side by side versions

mfavero · Post by **mfavero** » Tue Feb 10, 2015 2:20 pm

We are running multiple versions of DataStage all using just PX not the DS Server version.

7.5.2, 8.1.2 & now 9.1.2

I see that the shared memory parameters are different in 7.5 and 8.1 and when I install 9.1 they end up being the same as 8.1. Shouldn't the 9.1 values be different. I have found no guidance at IBM or in this forum for running multiple versions on the same server side by side.

Here are the values:
for 7.5.2
DMEMOFF 0x40000000
PMEMOFF 0x50000000
CMEMOFF 0x60000000
NMEMOFF 0x70000000

for 8.1.2
DMEMOFF 0x90000000
PMEMOFF 0xa0000000
CMEMOFF 0xb0000000
NMEMOFF 0xc0000000

for 9.1.2
DMEMOFF 0x90000000
PMEMOFF 0xa0000000
CMEMOFF 0xb0000000
NMEMOFF 0xc0000000

thanks for any guidance you can give

qt_ky · Post by **qt_ky** » Tue Feb 10, 2015 3:54 pm

Have you tried installing 11.3.1?

I think those are memory offset values (as opposed to absolute values) from some base value that I would assume is unique for each engine you've got up and running.

Are you finding any errors or problems that may be behind your question?

I would not expect any problems in this scenario. The latter values are what Ascential used to recommend changing the older out of the box values to.

mfavero · Post by **mfavero** » Wed Feb 11, 2015 11:20 am

I am not concerned or interested in v11 The key here is running multiple versions of PXEngine on the same server. If these memory variables are offsets then I would think they should be different for every version running. If they are the same then perhaps the Engines will conflict and walk over each others shared memory.

This is AIX 6.1 and I read that setting them to 0x0 would allow the OS to manage the memory. I do not know if this is recommended and have never seen them set that way

I would have thought one of the manuals would explain better than this comment in the uvconfig, but I cannot find anything.

# DMEMOFF - Specifies the shared memory attach point
# for the Disk Shared Memory Segment. This value
# should be specified in hex (ie, 0x4000000).
# This value should only be changed with a full
# understanding of the implications, as improper
# setting of this value can lead to the environment
# being unusable

Maybe I must try IBM support - I thought I would give this forum a go.

qt_ky · Post by **qt_ky** » Wed Feb 11, 2015 2:56 pm

The last time I discussed this with Support, which by the way was years ago, they were still recommending to use the following values that you now find in the uvconfig file out of the box.

DMEMOFF 0x90000000
PMEMOFF 0xa0000000
CMEMOFF 0xb0000000
NMEMOFF 0xc0000000

Since then I have run 8.5 and 8.7 side by side on the same AIX box, with the above default values. Likewise with multiple instances of 11.3.1 on the same AIX box, and am not seeing any problems.

Again, I am assuming they are offsets, or relative values that are offset from some number that is different for each instance. If you run it by Support to see if they have any new advice, please share.

chulett · Post by **chulett** » Wed Feb 11, 2015 3:36 pm

mfavero wrote:If these memory variables are offsets then I would think they should be different for every version running.

As noted they are offsets (xxxxOFF) from the base shared memory location of each installation not the same memory location between installations which is why there is no conflict.

mfavero · Post by **mfavero** » Fri Feb 13, 2015 2:09 pm

Thank you Craig. I was not experiencing a problem - just trying to understand the parameters better.

chulett · Post by **chulett** » Fri Feb 13, 2015 2:14 pm

Sure, understood that. Glad we could help.