We tried CMM-1 a month or two ago on a single guest. Without VMRM, there's nothing for it to talk to, so it does nothing. (It works by having VMRM send it notices to decrease working set size.)
With it enabled on one guest, on a machine slightly memory constrained, it drove the memory utilization of the guest down to the point that it wouldn't run at all. Obviously, it has to be enabled on a significant percentage of your guests to be useful. Most of ours are RHEL4 though, so (I believe) that's out of the question. We're still evaluating. -----Original Message----- From: Linux on 390 Port [mailto:linux-...@vm.marist.edu] On Behalf Of Michael MacIsaac Sent: Wednesday, September 23, 2009 10:51 AM To: LINUX-390@VM.MARIST.EDU Subject: Re: [LINUX-390] When will CMMA be removed from the kernel? Sam, > We load the CMM module via > /etc/sysconfig/kernel > MODULES_LOADED_ON_BOOT="vmcp cmm" > > So what is it that we have turned on? Good question. You've turned on CMM1 on Linux, but as I understand it, there must also be a *collaborative* piece enabled on z/VM. In both the latest Virtualization Cookbooks (ibm.com/redbooks), and the SLES 10 SP2 "read-only" root paper (linuxvm.org/present), there is a writeup on how to use CMM1 (much of this section was written by Ray Mansell - thanks Ray!). Search for "Enabling Collaborative Memory Management". It discusses how to also enable the collaborative piece: VMRM on z/VM. I'm curious that Barton wrote on August 28th: > VMRM has taken so much storage away from servers that the > server or application dies. I would HIGHLY recommend against using it. But he wrote today: > CMM-1 has very positive results So does CMM-1 have positive results without the collaborative piece? Barton, could you point to some numbers showing CMM-1 with positive results without VMRM? Did you use a different z/VM collaborative piece? Thanks. "Mike MacIsaac" <mike...@us.ibm.com> (845) 433-7061 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 -------------------------------------------------------------------------- This message w/attachments (message) may be privileged, confidential or proprietary, and if you are not an intended recipient, please notify the sender, do not use or share it and delete it. Unless specifically indicated, this message is not an offer to sell or a solicitation of any investment products or other financial product or service, an official confirmation of any transaction, or an official statement of Merrill Lynch. Subject to applicable law, Merrill Lynch may monitor, review and retain e-communications (EC) traveling through its networks/systems. The laws of the country of each sender/recipient may impact the handling of EC, and EC may be archived, supervised and produced in countries other than the country in which you are located. This message cannot be guaranteed to be secure or error-free. References to "Merrill Lynch" are references to any company in the Merrill Lynch & Co., Inc. group of companies, which are wholly-owned by Bank of America Corporation. Securities and Insurance Products: * Are Not FDIC Insured * Are Not Bank Guaranteed * May Lose Value * Are Not a Bank Deposit * Are Not a Condition to Any Banking Service or Activity * Are Not Insured by Any Federal Government Agency. Attachments that are part of this E-communication may have additional important disclosures and disclaimers, which you should read. This message is subject to terms available at the following link: http://www.ml.com/e-communications_terms/. By messaging with Merrill Lynch you consent to the foregoing. -------------------------------------------------------------------------- ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
