Kevin -- The technical answer is simply that When GT.M executes a commit to disk operation, for recovery from a subsequent system failure, it relies on that data being committed. This is the responsibility of an operating system, which in turn relies on the hardware. But in a virtual machine, the operating system talks to VMWare, not to the actual hardware, and a commit to disk on the virtual machine may or may not commit to disk on the actual machine. Therefore, the data that GT.M thinks is committed to disk may not actually be committed to disk, and if it is not, recoverability will be compromised. Now, with VMWare specifically, there may be a setting to perform a commit to the actual disk when there is a commit in the virtual machine, but I am not sure about this.
The business answer is that running in a virtual machine is just another risk that has a benefit. Just as a patient going in for a coronary bypass must weigh the risk of premature death on the operating table and painful recovery following successful surgery against the potential benefit of increased life span and enhanced quality of life, running a database engine in a virtual machine has risks and benefits. Perfection and absolute security don't exist - even sans a virtual machine, a lightning strike may fry your server, or your operating system may have a bug, and data that GT.M thought was committed turns out not to be so commmitted after all. Even with logical dual site operation of an application, and with the forthcoming logical multi site capability, there are no absolute guarantees. There are no correct answers, only difficult choices to be made. Making them intelligently requires a thorough understanding of the risks and benefits. -- Bhaskar On Fri, 2006-04-28 at 08:24 -0500, Kevin Toppenberg wrote: > But why demo only? The VWWare platform seems stable, if one can get > it all working. I just shouldn't have experimented during a business > day. The crash I experienced was as windows was sorting out > resources > etc. Our swap disk is also limited in disk space etc. So I suspect > all these issues could be resolved. > > I just want to go from 2 servers down to 1. > > Kevin > > > On 4/28/06, Mike Lieman <[EMAIL PROTECTED]> wrote: > > On 4/26/06, Bhaskar, KS <[EMAIL PROTECTED]> wrote: > > > For what it's worth, my opinion, nay advice, is that for > production, you > > > should use a native Linux machine. What we are talking about is > for > > > demo / development. > > > > > > > And I expect that "Last Generation" ( Pentium II, 500MHz ) machines > do > > just fine in that context. > > > > > > ------------------------------------------------------- > > Using Tomcat but need to do more? Need to support web services, > security? > > Get stuff done quickly with pre-integrated technology to make your > job easier > > Download IBM WebSphere Application Server v.1.0.1 based on Apache > Geronimo > > http://sel.as-us.falkag.net/sel?cmdlnk&kid0709&bid&3057&dat1642 > > _______________________________________________ > > Hardhats-members mailing list > > Hardhats-members@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/hardhats-members > > > > > ------------------------------------------------------- > Using Tomcat but need to do more? Need to support web services, > security? > Get stuff done quickly with pre-integrated technology to make your job > easier > Download IBM WebSphere Application Server v.1.0.1 based on Apache > Geronimo > http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 > _______________________________________________ > Hardhats-members mailing list > Hardhats-members@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/hardhats-members > ------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Hardhats-members mailing list Hardhats-members@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/hardhats-members
