1 / 16

Too Deep & Too Wide

Too Deep & Too Wide. Using Soft Limits To Avoid Hard Crashes. NY/NJ Websphere MQ Family User Group IBM 590 Madison Ave, New York City Tuesday March 25, 2003. T.Robert Wyatt, Vice President Bank Of America Differentiated Service Websphere MQ Support. Objectives.

cerise
Télécharger la présentation

Too Deep & Too Wide

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Too Deep & Too Wide Using Soft LimitsTo Avoid Hard Crashes NY/NJ Websphere MQ Family User GroupIBM 590 Madison Ave, New York CityTuesday March 25, 2003 T.Robert Wyatt, Vice PresidentBank Of America Differentiated ServiceWebsphere MQ Support NY/NJ MQ Family Users’ Group

  2. Objectives • Demonstrate why the default queue depth and message length values pose a potential risk • Discuss one approach to mitigating that risk NY/NJ MQ Family Users’ Group

  3. Scenario For Disaster Unrealistic requirements: “Need to be able to queue up an entire day’s worth of large XML messages” • Increase MAXDEPTH • Increase MAXMSGL NY/NJ MQ Family Users’ Group

  4. Whoops! One day the channel goes down and the system performs exactly as designed: • Queues begin to fill up • Underlying filesystem fills • MQ begins to cut FDC files • MQ and possibly the OS are halted NY/NJ MQ Family Users’ Group

  5. Recovery • Free up disk space any way possible • Move any diagnostic files • Delete non-essential files • Move older MQ logs if linear NY/NJ MQ Family Users’ Group

  6. Recovery When (or if) QMgr becomes responsive again: • Stop all channels • RCDMQIMG if linear • Shut down the QMgr NY/NJ MQ Family Users’ Group

  7. Recovery Restarting the QMgr: Delete files or add space • Clean up the file system • Remount the filesystem to larger disk and copy files Results in extended outage, high probability of client impact NY/NJ MQ Family Users’ Group

  8. What Happened? 5,000 x 4mb messages = 20GB 5k x 4mb persistent msgs > 40GB Def DeadQ 640,000 x 4mb = 2.5TB! When the capacity specified by soft limits exceeds the physical limits, then the soft limits do not exist. NY/NJ MQ Family Users’ Group

  9. Hard Limits Application constrained only by limits of physical disk space • Failure is sudden • Failure may be catastrophic • Affects OS & co-resident apps • Slow manual recovery • High client impact NY/NJ MQ Family Users’ Group

  10. Soft Limits Application constrained by MQ • System degrades gracefully • Failure isolated to specific apps within MQ • Recovery is automated – normal operation of MQ restores service • Minimal client impact NY/NJ MQ Family Users’ Group

  11. Tuning Discipline Insure soft limits < physical limits • Reduce MAXDEPTH, MAXMSGLor both • Reduce settings on SYSTEM.DEF*as well as application queues • Reduce DeadQ Settings! NY/NJ MQ Family Users’ Group

  12. Tuning Discipline Disk Space Available* MAXDEPTH MAXMSGL DSA = MAXMSGL x MAXDEPTHMAXDEPTH = DSA / MAXMSGLMAXMSGL = DSA / MAXDEPTH*Use ½ DSA for persistent msgs NY/NJ MQ Family Users’ Group

  13. Tuning Discipline Know your messages! • Soft limits must be appropriate to the business to be enforceable • Standardize, preferably automate • Verify on each machine • No exceptions Too shallow? Too narrow? Buy more disk! NY/NJ MQ Family Users’ Group

  14. Apply System Wide System-wide tuning parameters • Channel MAXMSGL • QMgr MAXMSGL • Max uncommitted messages • Log file size and extents • Use separate, preferably dedicated, filesystems for /var/mqm/qmgrs and /var/mqm/logs NY/NJ MQ Family Users’ Group

  15. Resources IBM Websphere MQ Manuals http://www-3.ibm.com/software/ts/mqseries/library/manualsa/ • Quick Beginnings Guide • System Administration Manual Support Pacs http://www-3.ibm.com/software/integration/support/supportpacs/ • Capacity planning pacs • Performance reports NY/NJ MQ Family Users’ Group

  16. Resources MQSeries.net: http://www.mqseries.net Vienna List Server: http://www-3.ibm.com/software/ts/mqseries/support/usergroups/listserver.html Download presentation: http://www.t-rob.net/Downloads/2Deep2Wide.ppt T.Rob: T.Rob@t-rob.net NY/NJ MQ Family Users’ Group

More Related