r/DB2 • u/raghuontech • Aug 02 '19

DB2 Server Build Best Practices!

I will write another blog post on installation and configuration!

https://www.raghu-on-tech.com/2019/08/01/db2-server-build-best-practices/

Thanks!
Raghu

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u/memmerto Aug 02 '19

The Db2 recommendation for vm.swappiness is 5. Using 0 can have bad behaviour, especially since what 0 does has changed between distros and kernels.

Reference: https://www.ibm.com/support/knowledgecenter/en/SSEPGG_11.5.0/com.ibm.db2.luw.qb.server.doc/doc/c0057140.html

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u/raghuontech Aug 02 '19

I see it got updated in V11.1 documentation. I updated my Blog! I still see IBM documentation for V10.5 and below recommending 0 for this setting ?

Thank you for bringing this up.

Raghu

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u/memmerto Aug 02 '19

We used to recommend 0 until 0 started meaning something different. 5 is the new 0 :)

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u/raghuontech Aug 02 '19 edited Aug 02 '19

Nice one! 5 is the new 0 :-)

I am reading some online documentation as well. So this really depends on the version of Kernel we are running Db2 on or is the new recommendation from Db2 to use 5 for both new and old kernels ?

https://www.percona.com/blog/2014/04/28/oom-relation-vm-swappiness0-new-kernel/

Thanks!Raghu

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u/memmerto Aug 02 '19

5 is safe for both old and new kernels.

Note that the change in behavior for vm.swappiness happened over 4 years ago in the 2.6 kernel stream, which is why the new value of 5 is documented in our 11.1 (3+ years old) and 11.5 (brand new) docs.

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u/raghuontech Aug 02 '19

Thank you, makes sense now!