Re: z/VM 5.2 and the 2GB Line
On Sat, Aug 23, 2008 at 9:40 PM, Schuh, Richard [EMAIL PROTECTED] wrote: Let's say that total amount of virtual storage is the main issue, with everything else relegated to the status of being inconsequential. The limit is on active virtual memory in the system. As Bill Holder says, it's determined by access density (or fragmentation, whatever you want to call it). There is two orders of magnitude difference between best case and worst case. And we found a system starting a bunch of big Linux servers to be close to the worst case. 100 GB real seemed to be a practical maximum in that situation. YMMV -Rob
Re: z/VM 5.2 and the 2GB Line
Let's say that total amount of virtual storage is the main issue, with everything else relegated to the status of being inconsequential. Regards, Richard Schuh -Original Message- From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Bill Holder Sent: Thursday, August 21, 2008 1:54 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: z/VM 5.2 and the 2GB Line On Thu, 21 Aug 2008 09:57:22 -0700, Schuh, Richard [EMAIL PROTECTED] wrot= e: I have been unable to come up with the magic search argument to get this= list to spit out the answer to the question, What is the total GB of virtual storage, the sum of the VM sizes, can z/VM 5.2 handle without running into the dreaded 2GB line constraint?, so I will ask the list. What is it? Regards, Richard Schuh The answer is, of course, the trademarked it depends. There are severa= l different forms of the constraint, and all are dependent on workload. Ev= en something as apparently unrelated as how dense or sparse the guests' stor= age reference patterns tend to be can greatly influence the degree to which t= he constraint will be an issue for a given total virtual storage size. I'm = not sure if we even have typical or average numbers, but I can ask around. = - Bill Holder, z/VM Development, IBM
Re: z/VM 5.2 and the 2GB Line
140GB didn't leave room for work, and make sure you have lots more expanded. Schuh, Richard wrote: Let's say that total amount of virtual storage is the main issue, with everything else relegated to the status of being inconsequential. Regards, Richard Schuh -Original Message- From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Bill Holder Sent: Thursday, August 21, 2008 1:54 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: z/VM 5.2 and the 2GB Line On Thu, 21 Aug 2008 09:57:22 -0700, Schuh, Richard [EMAIL PROTECTED] wrot= e: I have been unable to come up with the magic search argument to get this= list to spit out the answer to the question, What is the total GB of virtual storage, the sum of the VM sizes, can z/VM 5.2 handle without running into the dreaded 2GB line constraint?, so I will ask the list. What is it? Regards, Richard Schuh The answer is, of course, the trademarked it depends. There are severa= l different forms of the constraint, and all are dependent on workload. Ev= en something as apparently unrelated as how dense or sparse the guests' stor= age reference patterns tend to be can greatly influence the degree to which t= he constraint will be an issue for a given total virtual storage size. I'm = not sure if we even have typical or average numbers, but I can ask around. = - Bill Holder, z/VM Development, IBM
Re: z/VM 5.2 and the 2GB Line
On Thu, 21 Aug 2008 09:57:22 -0700, Schuh, Richard [EMAIL PROTECTED] wrot e: I have been unable to come up with the magic search argument to get this list to spit out the answer to the question, What is the total GB of virtual storage, the sum of the VM sizes, can z/VM 5.2 handle without running into the dreaded 2GB line constraint?, so I will ask the list. What is it? Regards, Richard Schuh The answer is, of course, the trademarked it depends. There are severa l different forms of the constraint, and all are dependent on workload. Ev en something as apparently unrelated as how dense or sparse the guests' stor age reference patterns tend to be can greatly influence the degree to which t he constraint will be an issue for a given total virtual storage size. I'm not sure if we even have typical or average numbers, but I can ask around. - Bill Holder, z/VM Development, IBM
