The ability to clone servers using mainframe dasd features such as STK snapshot, IBM Flashcopy(?) or even just good old DDR is another advantage of the maniframe. You don't have to re-do the installs and patches. Cloning takes less time and you know the servers are exactly the same. Just need reconfiguration for IP address,etc.
Another potential advantage is saving money on network switches - but only if you move a lot of servers to the mainframe. ---Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED] Behalf Of Richard Troth Sent: Monday, October 11, 2004 1:16 PM To: [EMAIL PROTECTED] Subject: Re: Linux Questions Cameron ... You need to look at the total picture: memory footprint (of the applications, and then of the "systems"), CPU usage (again of the apps and then op sys), I/O (again: scale it). If there is a lot of I/O to perform, or a lot of memory needed, zSeries (and z/VM) is probably a better fit. If you need to do a lot of computation, go for INTeL (or its clones). > Having troubles with promotion of Linux for zSeries in corporate > environment. I'm Hopeing someone here can point me to some good > documents on the strengths against an intel platform running VMWARE. Personally, I don't know where such documents are. (Maybe a Google search? Or someone who knows might chime in.) But the underlying hardware (zSeries -vs- INTeL, and their plug-compatible work-alikes) is so very different. Be aware. The mainframe is a "data mover". It has been tuned over the years to deal with tremendous volumes of data. The PC-class processor has been tuned for PC-class workloads. It is the better number cruncer because PC-class jobs use a LOT of processor power for all that interactive and display work. On virtualization (a grossly misused term now in the industry, but hopefully in this context we all understand), the mainframe has a great advantage. Doing virtual machines on PC-class processors is hard work. Not all guest operating systems are supported by VMware. (To note: ye olde OS/2.) And you cannot run VMware-on-VMware, but whether that is an artificial restriction or a real one, I don't know, and either way, there is a performance question. Don't get me wrong: I am very impressed with what VMware has done. And I'm not ragging on INTeL for its design. Just that the INTeL design does not lend itself to "self virtualization". > There have > been Questions come up about performance, Oracle, How many guests can we > put out there and what kind of performance loss per guest do we get or > can we expect? Just want to justify in spending a quarter of a million on > the hardware and be able to get what we need out of it. Does anyone know > of some good docs pointing to these answered questions. There are lots and lots of performance issues with running multiple copies of anything. Guest operating systems present a pathological case: they're demanding. I'm a big believer in zSeries and especially z/VM. But most of us on the list will tell you it will not solve all your problems. (Nor will VMware.) As recently as two years ago, VMware did not advertise more than a half dozen virtual machines on any single physical processor. It may be different for ESX than for GSX (or certainly "Workstation"). By contrast, z/VM WILL RELIABLY RUN dozens, hundreds, or even several thousand guest operating systems simultaneously. > -Cameron I hope this helps. Simplistically: z/VM wins where the guest systems will have a large memory footprint or will be doing a lot of I/O, or where you need many. VMware wins where you only need a few and you need the numeric capabilities of the PC-class processor or if you are "starting cheap". -- R; HCPMCV1459E ---------------------------------------------------------------------- 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 This communication, including attachments, is for the exclusive use of addressee and may contain proprietary, confidential or privileged information. If you are not the intended recipient, any use, copying, disclosure, dissemination or distribution is strictly prohibited. If you are not the intended recipient, please notify the sender immediately by return email and delete this communication and destroy all copies. ---------------------------------------------------------------------- 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
