We've been over this several times in this list. The beauty of Linux on z/VM is not how much computing power the mainframe has. actually, mainframes don't have a lot of computing power. However, if you run an application that does a LOT of I/O, say a webserver that serves out a LOT of files or accesses a database, then the mainframe comes into its glory. The mainframe is all about I/O processing. If you add in the channel processors, the service processor, all the controllers and the like, a 350-Mips mainframe is actually about 20,000 mips, but it's ALL I/O! We have Unix servers here that have to have as many as 20 "mirror sites" because the main server (where the central processor handles compute AND I/O tasks) can't handle the I/O load. Consolidate it on the mainframe and you only need one server. Any time you have 20 copies of the same data with people doing updates, at least 19 of those copies will be wrong!
Furthermore, the REAL beauty is that most Unix or NT servers are sized to the peak load, not the average load. If you have a server that for 15 minutes every day runs 85% busy and is mostly idle the rest of the time, you have to size the server to that 85% to meet the load. The rest of the time you spent too much. With VM, you can run LOTS of servers that are really cheap when idle, but have all that capacity when you need it. Almost all the time you will not have two servers require peak capacity at once. We are currently running 25 Linux servers on a single-IFL LPAR and hardly ever go above 8% processor usage. Every now and then something jumps it up to 50% or even 90% usage, but it's over quick. We're basically SHARING the excess capacity among a LOT of servers. Mainframe Linux isn't trying to be a racecar, but more like a semi. Don't use it for compute-intensive jobs, but for consolidating capacity and doing heavy I/O jobs. They say there are three signs of stress in your life. You eat too much junk food, you drive too fast and you veg out in front of the TV. Who are they kidding? That sounds like a perfect day to me! Gordon Wolfe, Ph.D. (425)865-5940 VM & Linux Servers and Storage, The Boeing Company > ---------- > From: Noll, Ralph > Reply To: Linux on 390 Port > Sent: Friday, April 4, 2003 12:10 PM > To: [EMAIL PROTECTED] > > so then why am i running my linux on a z/series and not x/series?? > z series and VM is what IBM was selling to so that is what we bought > > not trying to be rude... just commenting > > Ralph > > > -----Original Message----- > > From: Jim Elliott [mailto:[EMAIL PROTECTED] > > Sent: Friday, April 04, 2003 1:56 PM > > To: [EMAIL PROTECTED] > > Subject: > > > > > > From: "Noll, Ralph" <[EMAIL PROTECTED]> > > Subject: Re: performance > > > > > the performance of linux on s390 doesn't seem to be as fast > > as an x86 > > > box > > > > > i am using suse sles8 31 bit for s/390 on a z/800 0a1 running vm 4.3 > > > with 2 vse's and 6 linux instances when i do the ind command.. > > > following.. doesn't look busy > > > > Ralph: > > > > A z800-0A1 is equivalent (in pure compute power) to a 280MHz Intel > > system. Don't forget, this is the second smallest system IBM sells > > today in the zSeries family. > > > > Regards, Jim > > > >
