As with all questions about performance, the answer is: "it depends" (tm--Bill Bitner, IBM Endicott). The time it takes to clone a Linux image can be broken down into the following parts: 1) create the new virtual machine definition 2) copy whatever read/write disks are needed 3) do the Linux network configuration for the new Linux image
Steps 1 and 3 usually take at most 1 or 2 seconds of processor time, even on the smallest S/390 systems, as these steps don't involve much work. Step 2, copying the read/write disk(s) can take anywhere from a few 10s of seconds, to 10 to 20 minutes, depending on the disk hardware in use and the method of disk copying employed (DDR, PIPE trackread/trackwrite, etc.). If the disks are "small" and the dasd hardware a SHARK or similar caching device, then the changes are good that the entire disk will fit inside the device' cache, making copying it very fast for the 2nd and later times. If the device is a real 3380/3390 and the disk is an entire pack then the copy time will be measured in minutes and not seconds. On the other hand, new devices (e.g., StorTek's dasd systems) support an almost "instant" or "flashcopy" function, so that creating a new Linux clone image can be completed in 1-2 seconds on a z800 processor. Hope this helps. Dave Jones Sine Nomine Houston, TX ----- Original Message ----- From: "Phil Payne" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Wednesday, September 04, 2002 11:32 AM Subject: Re: The redpaper for cloning zLinux images via VQDIO is available > > The redpaper for cloning zLinux images by using VQDIO is available from > > http://www.ibm.com/redbooks/abstracts/redp0301.html. This redpaper is based > > from the LinuxWorld zLinux cloning example (using IUCV) that I released in > > 5/5/2002 (http://www.vm.ibm.com/devpages/chongts/tscdemo.html) . Have Fun! > > Quick 'analyst' question (I'll download and read it when I have the time, but not until next > week at the earliest): > > Roughly how quickly could a new Linux image be established using this technique on, e.g., a > z800? > > -- > Phil Payne > http://www.isham-research.com > +44 7785 302 803 >
