The swapping option in vmware server, for example, is using the pagefile on the HOST to be able to add memory and let the vm's swap in and out of ram.
Enabling this on vmware server and actually using it Ive seen takes my server about 12 minutes to boot. Totally unreasonable, so I would just always disable ram sharing. ESX 2.53+ does this much better and although an obvious performance hit, I have done it on production machines without anyone knowing. _____ From: Matthew W. Ross [mailto:[EMAIL PROTECTED] Sent: Wednesday, May 14, 2008 3:05 AM To: NT System Admin Issues Subject: RE: HIJACKED THREAD: Virtual Memory and Virtual Machines (WAS: RE: Why XP is doomed) In my case, I don't have a SAN. Just a decent raid controller, and a bunch of smaller VMs doing single tasks. Also, there are options in VMWare to allow/disallow swapping of memory of the guest OS. I don't know if Microsoft's Server 2008 VM has that setting. --Matt Ross _____ From: Ken Schaefer [mailto:[EMAIL PROTECTED] To: NT System Admin Issues [mailto:[EMAIL PROTECTED] Sent: Tue, 13 May 2008 23:40:33 -0700 Subject: RE: HIJACKED THREAD: Virtual Memory and Virtual Machines (WAS: RE: Why XP is doomed) So, you are talking about: a) Disabling the page file inside VMs (A), (B) and (C) b) Hoping that the OSes inside those machines never need more than 512MB of RAM ? I suppose it's possible. But do you want to risk it? I'm not sure you'd gain very much. Most people put the VMs on a SAN (for performance as well as HA reasons), so raw IOps shouldn't be an issue. Cheers Ken From: Matthew W. Ross [mailto:[EMAIL PROTECTED] Sent: Wednesday, 14 May 2008 4:37 PM To: NT System Admin Issues Subject: HIJACKED THREAD: Virtual Memory and Virtual Machines (WAS: RE: Why XP is doomed) Oooh... that brings up some questions... I've always wondered if anybody has looked at Virtual Machines, and the use of Page files... Let me explain. Let's say we have a box with 4 virtual machines. Each virtual machine is given 512 megs of Memory, and is running windows 2003. The host server has 4 gigs of ram, so the 2 gigs being used by the VMs is no problem, and plenty of room to spare. Of the four MVs, you have: A) A DHCP/DNS/WINS server B) An Active Directory server C) An IIS server serving simple static pages D) An SQL Server with a moderately heavy database Could someone take VMs A, B, and C and give them a ZERO page file increasing performance for all parties? This is assuming that the jobs that VMs A, B, and C are all able to run their important but trivial tasks directly from memory, while VM D has less to compete with for IO to the harddrives? Has anybody done this kind of thing with success? Just a thought. It's ripe for the squashing. Sm:)e. --Matt Ross ~ Upgrade to Next Generation Antispam/Antivirus with Ninja! ~ ~ <http://www.sunbelt-software.com/SunbeltMessagingNinja.cfm> ~
