Category Archives: Oracle

Infrastructure as a Service (IaaS) – Why? What about security? What about SOA?

IaaS or “Infrastructure as a Service” is a concept and frequently offered product in the Cloud Computing space that currently appears to have as much pervasiveness as any of the other service types. Continue reading →

Posted in Architecture, Cloud Computing, J2EE, Java, Linux, Oracle | Tagged , , , , , , | Comments Off

AIX 5.3 ORA-27126: unable to lock shared memory segment in core

you set lock_sga=true didn’t you?

This doesn’t appear to be documented many places, so I’ll put it here. There can be a tangible performance increase to ‘locking’ SGA to pinned memory. Paging spaces are, after all, on a slower medium (disk). In AIX 5.3 you also need to ‘pin’ shared memory. (SGA is shared memory) Continue reading →

Posted in AIX, Oracle, Tuning, UNIX | Tagged | 1 Comment

Mainframe Modernization And Migration Considerations

So… you have a mainframe application and you want to modernize it or migrate it to a distributed systems architecture… congratulations. Here are some things you may want to consider before making the foolish move of comparing MIPS to SPECint … Continue reading →

Posted in AIX, DB2, J2EE, Java, Legacy, Linux, Mainframe, Oracle, Sizing, UNIX | Tagged , | Comments Off

Using R to look at your vmstat data…

So – you’ve collected some vmstat data (with timestamps, of course) and you want to show the information in R. Well here’s how I did it. In this case, the purpose was to prove the weak correlation between the CPU … Continue reading →

Posted in AIX, Linux, Oracle, Perl, Scripts, Solaris, Tuning, UNIX, WebSphere | Tagged , , , | Comments Off

AIX numperm%

numperm% is the percentage of RAM used for FS Cache. You can check its current value with vmstat -v. There doesn’t appear to be any real benefit to forcing the minperm and maxperm to be lower unless you see the … Continue reading →

Posted in AIX, DB2, Oracle, Tuning, WebSphere | Tagged , , , , , | 2 Comments