Since workloads vary thought the day it is very hard to say one way or the other what is best. The rule of thumb of course to give the machine doing the most productive work the highest share. It is also important to remember that the busier your z/VM system the more important the sharing becomes. If your CPU is only 10% busy it doesn't matter much what you do with your share settings, there is plenty of power to go around. On the other hand if you are pushing the 100% utilization you need to be more careful with who gets what. As Catharine mentioned we are using z/VM Resource Manager, a free part of z/VM (starting with 5.2 I think). After setting some simple rules for the Recourse Manager to follow I can pretty much forget about share settings. VMRM dynamically changes the settings, as per your rules. There are certain machines you don't want VMRM to look at, i.e. TCPIP or VTAM etc. and you can manually set those as you prefer and not allow VMRM to interfere. I hope this helps
-----Original Message----- From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] Behalf Of McBride, Catherine Sent: Thursday, August 02, 2007 8:02 AM To: [email protected] Subject: Re: SET SHARE RELATIVE Anne we've experimented with SET SHARE ABSOLUTE (with and without LIMITSOFT and LIMITHARD) over the years to cap off something that gets too capricious. But there's probably much better ways to address this. We use VM Resource Manager, which has some "stuff" to help manage the guests. Hopefully some of the more knowledgable VM people will jump into this, including my pal on the other side of the cubicle wall... -----Original Message----- From: The IBM z/VM Operating System [ mailto:[email protected] <mailto:[email protected]> ]On Behalf Of Anne Crabtree Sent: Thursday, August 02, 2007 7:56 AM To: [email protected] Subject: SET SHARE RELATIVE We have five linux instances running, two of which aren't really being used, two are production and one is test. In the test linux instance, they are running a web app (which I know nothing about). At certain times during the day, this test instance will take close to 100% of the IFL. We want to back it off so that it can take no more than 50% to see how that affects them. Would it be logical to issue SET SHARE linux RELATIVE 50 since it is defaulting to REL 100? Will that do what I think and limit it to half of what the other virtual machines "get"? Anne D. Crabtree System Programmer WV Dept of Administration - OT 304-558-1494 Fax 304-558-1441 _____ << ella for Spam Control >> has removed 12458 VSE-List messages and set aside 11315 VM-List for me You can use it too - and it's FREE! www.ellaforspam.com <http://www.ellaforspam.com>
