>Hi Carsten, i just don't believe that under stress conditions >that in today's environement you can show value to paging >to dcss over vdisk. This being with z/vm 5.1 and a current >redhat or suse. Why don't you measure it? My simple measurements (I am not a performance guy but the developer) indicate a strong benefit.
>The ibm recomendations i keep hearing being repeated are that >swap sizes must be some multiple of the linux virtual machine >size. So if my Oracle server requires 2GB, then (some) ibm do >says i should have 4GB of swap. and in today's environement, i >can not have a discontigous virtual machine, so swap dcss must >be at the top of virtual storage. but that would be over the 2gb >line. not possible - with what is available or announced as far >as i know. mixing dcss and vdisk seems to create a more complex >environment than most installations want to utilize. after all, >vm is just a hypervisor i'm told. Sles9 will allow to have discontiguous storage very soon. So does Rhel4. And Vanilla Linux does have it since 2.6.6. Your statement is clearly outdated. >even if discontigous machines were supported by linux and z/vm, >i still don't have 2gb available of virtual storage for the dcss, >unelss you eliminate all need for linux to address storage below >the 2gb line? That's true. You need to have approx 64megs stoage below, but that's not a significant amount. >In real production environements, i currently have a serious >problem with storage and minimizing storage requirements. i >believe that with the current vdisk and dcss page stealing >algorithms, that dcss will retain more real storage than vdisk. >much more. and i think vdisk could be greatly improved upon. Discussion with the VM development team indicates that things are just the other way round. They believe DCSS would be more elegant for their page stealing algos - unless I got them completely wrong. >so really, my main point i'm trying to make is that a real >measurement showing value is worth a lot of opinions.... >i have mine, you have yours, rob has his, let's duke it out on >the benchmark battlefield.... show real data???? winner buys >the beer? I would really love to prove my point by a performance measurement, but I believe people are much better off when I keep developing good soloutions that integrate Linux and VM instead of trying to prove my points by performance measurements. Maybe you should visit one of either Rob's or my presentations to learn about current development. with kind regards Carsten Otte -- omnis enim res, quae dando non deficit, dum habetur et non datur, nondum habetur, quomodo habenda est ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
