Yet another reason for Linux on zSeries is that it can have workload benefits for z/OS, z/VSE, z/TPF, and z/VM (CMS) applications. Specifically, Linux on zSeries enjoys Hipersockets (high speed in-memory connectivity) across LPARs to other mainframe subsystems and applications, such as DB2 UDB for z/OS. If any of the Linux applications require such backend services then "proximity" makes a lot of sense. Sometimes you also get benefits with the more complex multi-server enterprise applications -- in-memory connections are quite helpful (such as with EJBs).
Proximity means a couple things. One is that those mainframe subsystems have to work less hard servicing requests that originate "onboard" rather than offboard. Or, said simply, you save CP MIPS. (Basically you hold locks, generically speaking, for shorter durations and the overall path length is shorter.) The second benefit is that users can experience fewer delays because you've knocked out some latencies (such as physical network interactions which can involve several roundtrips per user). That means they can get improved response times. The Washington Systems Center has some good sample benchmarks that demonstrate these effects. Often even partial implementation of proximity is beneficial. DB2 Connect for Linux on zSeries is a good example. There's also the security aspect. I'm running into many cases where encryption is now mandatory for any physical network hop, including those within a datacenter. That's hard to pull off when you've got more than a couple distributed servers to lash together. - - - - - Timothy F. Sipples Consulting Enterprise Software Architect IBM Americas zSeries/z9 Software Phone: +1 312 405 0750 Voice Messages: +1 312 529 1612 E-Mail: [EMAIL PROTECTED] ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
