1. PIA Load Balancing, JVMs and Garbage Collection David Kurtz Go-Faster Consultancy Ltd. david.kurtz@go-faster.co.uk www.go-faster.co.uk

2. PSFT Tech PUG 5.9.05 www.go-faster.co.uk2 Who am I? DBA –Independent consultant System Performance tuning –PeopleSoft ERP –Oracle RDBMS Training Course UK Oracle User Group –Unix SIG Oak Table –www.oaktable.net Book –www.psftdba.com

3. PSFT Tech PUG 5.9.05 www.go-faster.co.uk3 Resources If you can’t hear me say so now. Please feel free to ask questions as we go along. The presentation will be available from –www.go-faster.co.ukwww.go-faster.co.uk

4. PSFT Tech PUG 5.9.05 www.go-faster.co.uk4 A War Story Two forms of load balancing –Windows Network Load Balancing –IIS Proxy PSFT Recommendations: –Red Paper HA & Clustering WEB1 PIA1 50.0.0.7:7001 PIA2 50.0.0.7:17001 IIS 50.0.0.7:443 WEB2 PIA1 50.0.0.8:7001 PIA2 50.0.0.8:17001 IIS 50.0.0.8:443 Windows NetworkLoad Balancing 50.0.0.50:443

5. PSFT Tech PUG 5.9.05 www.go-faster.co.uk5 Problems Strange Pauses –Mostly to do with garbage collection IIS Proxy wouldn’t load balance –All of load on one PIA or the other Pauses cause IIS Proxy failover On Failover users loose their sessions

6. PSFT Tech PUG 5.9.05 www.go-faster.co.uk6 IIS Load Balancing iisproxy.ini WebLogicCluster=50.0.0.8:7001,50.0.0.8:17001 DynamicServerList=OFF …

7. PSFT Tech PUG 5.9.05 www.go-faster.co.uk7 IIS Load Balancing Uneven loading of PIAs caused overload of one PIA. Duration of garbage collection with 100% of load on single PIA much higher

8. PSFT Tech PUG 5.9.05 www.go-faster.co.uk8 How do I know the load is balanced? Web server access log PeopleSoft Performance Monitor PT>=8.44 –Event 150: JVM Status –Event 152: Web Site Status –Event 153: Web Servlet Status

9. PSFT Tech PUG 5.9.05 www.go-faster.co.uk9 How do I know the load is balanced?

10. PSFT Tech PUG 5.9.05 www.go-faster.co.uk10 JVM Garbage Collection Java Command Line Options –verbosegc Writes to weblogic.log –Xloggc: 0.000: [GC 46591K->3553K(518464K), 0.1262603 secs] 19.604: [GC 50145K->6662K(518464K), 0.3389070 secs] 70.052: [Full_GC 46565K->10901K(518464K), 0.9507536 secs] 90.967: [Full_GC 55273K->16571K(518464K), 1.1008306 secs]

11. PSFT Tech PUG 5.9.05 www.go-faster.co.uk11 Garbage Collector Log 90.967: [Full_GC 55273K->16571K(518464K), 1.1008306 secs] –Elapsed time since JVM started –Collection type –Size of live objects before and after GC –Total space available, less permanent objects –Duration of collection

12. PSFT Tech PUG 5.9.05 www.go-faster.co.uk12 Timestamps on GC log -XX:+PrintGCTimeStamps But I couldn’t get it to work!

13. PSFT Tech PUG 5.9.05 www.go-faster.co.uk13 Other Garbage Collection Options -XX:+UseConcMarkSweepGC -XX:+UseParNewGC -XX:+CMSParallelRemarkEnabled Caveat: These options are not presented as being any kind of panacea, but something to consider. You need to do your own testing. BTW: I got the idea for this from a UKOUG Oracle Application Server SIG!

14. PSFT Tech PUG 5.9.05 www.go-faster.co.uk14 -XX:+UseConcMarkSweepGC Concurrent Low Pause Collector GC is, as far as possible, concurrent with the execution of the application. –Uses a separate thread App is paused for shorter periods during GC Only effective on multi-processor machines

15. PSFT Tech PUG 5.9.05 www.go-faster.co.uk15 -XX:+UseParNewGC Parallel young generation GC with concurrent GC –for multiprocessor machines, –enables multi threaded young generation collection –Application is not paused

16. PSFT Tech PUG 5.9.05 www.go-faster.co.uk16 -XX:+CMSParallelRemarkEnabled Reduces remark pauses

17. PSFT Tech PUG 5.9.05 www.go-faster.co.uk17 Default Garbage Collector Individual GC duration

18. PSFT Tech PUG 5.9.05 www.go-faster.co.uk18 Parallel Garbage Collector Individual GC duration

19. PSFT Tech PUG 5.9.05 www.go-faster.co.uk19 Default Garbage Collector Cumulative GC duration / minute

20. PSFT Tech PUG 5.9.05 www.go-faster.co.uk20 Parallel Garbage Collection Cumulative GC duration / minute

21. PSFT Tech PUG 5.9.05 www.go-faster.co.uk21 Conclusion Improved GC performance does not have a great effect on Component Performance It does reduce the ‘strange pause’ giving the user a better experience Parallel GC seems to slowly leak memory. –Possible bug in a particular JVM –I have only tested on Windows

22. PSFT Tech PUG 5.9.05 www.go-faster.co.uk22 Questions?

23. PIA Load Balancing, JVMs and Garbage Collection David Kurtz Go-Faster Consultancy Ltd. david.kurtz@go-faster.co.uk www.go-faster.co.uk