Re: Define/Remove CPU from an MVS Guest
On Wednesday, 06/04/2008 at 10:38 EDT, Wandschneider, Scott [EMAIL PROTECTED] wrote: In other words there is no way to remove a CPU without an IPL - is that correct? Correct. To add/remove CPUs dynamically requires use of specific z/Architecture that allows that to occur, but CP doesn't virtualize that architecture. It would be highly inappropriate to rip a CPU out from under a system without telling it the CPU is leaving/gone. So, we reset the guest to avoid any potential for unpredictable results. We do know that it would be a Good Thing to have that capability so that a guest could shrink or grow its CPU consumption as the number of CPUs in the LPAR shrinks or grows. Alan Altmark z/VM Development IBM Endicott
Re: Define/Remove CPU from an MVS Guest
Thank you Allan. Thank you, Scott R Wandschneider Senior Systems Programmer Infocrossing Office 402.963.8905 -Original Message- From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Alan Altmark Sent: Thursday, June 05, 2008 9:33 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Define/Remove CPU from an MVS Guest On Wednesday, 06/04/2008 at 10:38 EDT, Wandschneider, Scott [EMAIL PROTECTED] wrote: In other words there is no way to remove a CPU without an IPL - is that correct? Correct. To add/remove CPUs dynamically requires use of specific z/Architecture that allows that to occur, but CP doesn't virtualize that architecture. It would be highly inappropriate to rip a CPU out from under a system without telling it the CPU is leaving/gone. So, we reset the guest to avoid any potential for unpredictable results. We do know that it would be a Good Thing to have that capability so that a guest could shrink or grow its CPU consumption as the number of CPUs in the LPAR shrinks or grows. Alan Altmark z/VM Development IBM Endicott
Re: Define/Remove CPU from an MVS Guest
In other words there is no way to remove a CPU without an IPL - is that correct? Thank you, Scott R Wandschneider Senior Systems Programmer Infocrossing Office 402.963.8905 -Original Message- From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Alan Altmark Sent: Wednesday, June 04, 2008 12:23 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Define/Remove CPU from an MVS Guest On Tuesday, 06/03/2008 at 05:26 EDT, Wandschneider, Scott [EMAIL PROTECTED] wrote: I now know that the MACHINE ESA 4 statement authorizes the guest to use up to four CPUs. I successfully executed a DEFINE CPU 03. However, MVS could not configure the 4th CPU online since it did not know about it at IPL time. Okay but, with the 4th CPU defined and not doing anything, how would one go about safely removing CPU 03 short of an IPL? Yes, I tried the DETACH CPU 03 command and watched the MVS system IPL. You don't. If you DETACH a CPU, the virtual machine will RESET. (If you have SET CONCEAL ON or OPTION CONCEAL, that will cause the guest to re-IPL automatically.) Alan Altmark z/VM Development IBM Endicott
Define/Remove CPU from an MVS Guest
I had an MVS guest setup with the following directory statements: MACHINE ESA 4 CPU 00 BASE CPU 01 CPU 02 I now know that the MACHINE ESA 4 statement authorizes the guest to use up to four CPUs. I successfully executed a DEFINE CPU 03. However, MVS could not configure the 4th CPU online since it did not know about it at IPL time. Okay but, with the 4th CPU defined and not doing anything, how would one go about safely removing CPU 03 short of an IPL? Yes, I tried the DETACH CPU 03 command and watched the MVS system IPL. Thank you, Scott R Wandschneider Senior Systems Programmer Infocrossing Office 402.963.8905
Re: Define/Remove CPU from an MVS Guest
On Tuesday, 06/03/2008 at 05:26 EDT, Wandschneider, Scott [EMAIL PROTECTED] wrote: I now know that the MACHINE ESA 4 statement authorizes the guest to use up to four CPUs. I successfully executed a DEFINE CPU 03. However, MVS could not configure the 4th CPU online since it did not know about it at IPL time. Okay but, with the 4th CPU defined and not doing anything, how would one go about safely removing CPU 03 short of an IPL? Yes, I tried the DETACH CPU 03 command and watched the MVS system IPL. You don't. If you DETACH a CPU, the virtual machine will RESET. (If you have SET CONCEAL ON or OPTION CONCEAL, that will cause the guest to re-IPL automatically.) Alan Altmark z/VM Development IBM Endicott
