On Friday 15 September 2006 2:15 am, Pavel Emelianov wrote: > I do not 'do not like guarantee'. I'm just sure that there are two ways > for providing guarantee (for unreclaimable resorces): > 1. reserving resource for group in advance > 2. limit resource for others > Reserving is worse as it is essentially limiting (you cut off 100Mb from > 1Gb RAM thus limiting the other groups by 900Mb RAM), but this limiting > is too strict - you _have_ to reserve less than RAM size. Limiting in > run-time is more flexible (you may create an overcommited BC if you > want to) and leads to the same result - guarantee.
I realize I'm jumping in late to a discussion that has apparently been going on for a long time. I may be missing some pieces of the puzzle, but from where I'm standing this is what I see... I think you're missing the point a bit. To me a guarantee on a resource does exactly your #1. A system administrator has declared that this container gets X amount of this resource to the detriment of the rest of the system, whether it chooses to use it or not. I don't think it's possible to emulate this semantic in any way other than to reserve the resource in advance. On your web page you mention resources that can not be reserved, ie CPU and disk or network bandwidth. I recall some of the old network standards that spelled out how to implement guaranteed quality of service. It stated that all guaranteed clients got serviced first up to their guarantee, then the remainder (if any) could be used by the non-guaranteed clients. If we follow this method, it is up to the administrator (or the administrative tools) to ensure that the sum of the guarantees does not result in an overcommitted system. This follows the philosophy of letting people shoot themselves in the foot if they truly wish to. To reiterate: guarantees are inherently unfair by definition. They do penalize the rest of the sytem by design. Any attempt to smooth over their impact defeats their purpose. Dave McCracken ------------------------------------------------------------------------- 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 _______________________________________________ ckrm-tech mailing list https://lists.sourceforge.net/lists/listinfo/ckrm-tech
