AIXpert Blog is about the AIX operating system from IBM running on POWER based machines called Power Systems and software related to it like IBM Systems Director, PowerVM for virtualisation and PowerSC for security plus performance monitoring and nmon
One way to determine if there is an I/O bottleneck in AIX's Logical Volume Manager (LVM) layer is to run the "filemon" command. The filemon output shows I/O response times for both Logical Volume (LV) and Physical Volume (PV) layers. If the difference is over 2-3 ms, there could be an I/O bottleneck in LVM. If so, check the LVM buffer statistics at peak I/O loads. Run the "vmstat -v" several times, and look for increasing "I/Os blocked" in any of the buffers. (The rate of change is important, not absolute values). Use the "ioo" command to... [More]
Here is Jaqui Lynch's AIX 5.3 initial tuning guidelines for commercial workloads. Jaqui wrote and delivered the "AIX Performance Tuning" session at the "IBM System p, AIX, Linux Technical University" this year in Las Vegas. no -p -o rfc1323=1no -p -o sb_max=1310720no -p -o tcp_sendspace=262144no -p -o tcp_recvspace=262144no -p -o udp_sendspace=65536no -p -o udp_recvspace=655360nfso -p -o nfs_rfc1323=1nfso -p -o nfs_socketsize=60000nfso -p -o nfs_tcp_socketsize=600000vmo -p -o minperm%=5vmo -p -o minfree=960vmo -p -o maxfree=1088vmo -p -o... [More]
I want to remind you of the value of pSeries Subscription Services. Recently, those of us subscribed to receive 'Critical Fixes' got a note pointing to this URL: http://techsupport.services.ibm.com/server/criticalfixes3/critfixes/5300-02.html This listed 36 Critical Fixes of which two were Critical Security Fixes: IY68463 AIX 5.3 SECURITY: Local root exploits in perl 5.8.x IY70026 AIX 5.3 Attacks against TCP via ICMP Other critical security fixes recently announced through subscription service IY68825 AIX 5.3 Remote... [More]
The System p Support site has migrated to a new subscription service tool for support notifications named My notifications You'll need an IBM Developerwork's ID. (It's free and painless to register a new ID) Subscriptions for IBM Systems provides the following new features: - Ability to create multiple subscriptions with different topics and notification options- Ability to create and name multiple folders to organize your subscriptions- Ability to specify weekly or daily notifications when a topic is updated- Ability to access the PTF Cover... [More]
If you are using AIX sendmail, you should consider the following fix to prevent spammers from using it as an open mail relay. ftp://aix.software.ibm.com/aix/efixes/security/sendmail_3_mod.tar.Z /a> The exposure applies to AIX 5.3 ML1 and earlier distributions. The exposure was resolved in AIX 5.3 ML2. For more information, see http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2003-0285
I have tried to get permission to pass on these numbers publically but got no answer at all. As these are facts rather than opinions, I see no harm in them. So I will work on the old theory: "it is easier to ask for forgiveness than permission" ... here goes.
The AIX Virtual User Group often asks a few questions as part of the registration process for the next webinar session and it generates fascinating statistics from real POWER and AIX users.
The people that join the AIX Virtual User Group are... [More]
Here is a great index page for AIX information. Most ofthe links are to www.ibm.com ... but you get to avoid theIBM search engine :-) One of the very nice features is that every link (or leastevery one I tried) opens a new window. http://www.aix.lap.hu There is also a Google-based search engine for AIX: http://www.aixsearch.com
Support for the new Power5+ Servers: http://w3-03.ibm.com/support/techdocs/atsmastr.nsf/WebIndex/FLASH10519 HACMP supports the IBM System Storage DS4200 Express http://w3-03.ibm.com/support/techdocs/atsmastr.nsf/WebIndex/FLASH10514 HACMP supports SVC 3.1 & Metro Mirror Express http://w3-03.ibm.com/support/techdocs/atsmastr.nsf/WebIndex/FLASH10513 HACMP supports the JS21 BladeCenter Express http://w3-03.ibm.com/support/techdocs/atsmastr.nsf/WebIndex/FLASH10512 HACMP supports the IBM System Storage DS4700... [More]
One customer was experiencing slow performance for the gcc build script and the Apache configure script. The problem was resolved by exporting the following variables. export CONFIG_SHELL=/opt/freeware/bin/bash export CONFIG_ENV_ARGS=/opt/freeware/bin/bash The performance for the Apache configure script went from 2 1/2 hours to 3 minutes. The performance for the gcc and gcc++ build went from 4-5 hours to 35 minutes. The performance for the full blown gcc build using NFS went... [More]
AIX5L Practical Performance Tools and Tuning GuideRevised: November 2, 2006 ISBN: 0738491799 738 pagesExplore the book online at http://www.redbooks.ibm.com/abstracts/sg246478.html Certification Study Guide: System p5 Admin & Support for AIX v5.3Revised: October 31, 2006 ISBN: 0738496499 720 pagesExplore the book online at http://www.redbooks.ibm.com/abstracts/sg247199.html
The following paper by Ralf Schmidt-Dannert discusses the performance impact of AIX micropartition options on a 2 tier Java/C++/Oracle application. His benchmarks show micropartitioningcan have a positive impact on application performance. His conclusionsinclude: 1. The micropartition CPU sharing improved performance over static LPARs2. SMT improved performance (default AIX setting)3. Don't over configure Virtual Processors (My recommendation is to configure at most one Virtual Processor per CPU in the free pool)... [More]