Comments on: Why My Two vCPU VM is Slow http://lonesysadmin.net/2008/04/22/why-my-two-vcpu-vm-is-slow/ Virtualization, System Administration, and Technology. Wed, 01 Sep 2010 16:17:18 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: Bob Plankers http://lonesysadmin.net/2008/04/22/why-my-two-vcpu-vm-is-slow/comment-page-1/#comment-74084 Bob Plankers Wed, 23 Apr 2008 20:44:51 +0000 http://lonesysadmin.net/?p=1234#comment-74084 Yeah, I think I've blogged about it before, but I ran into a customer who was having this problem and thought it'd be helpful to repeat. :-) Yeah, I think I’ve blogged about it before, but I ran into a customer who was having this problem and thought it’d be helpful to repeat. :-)

]]> By: Scott Lowe http://lonesysadmin.net/2008/04/22/why-my-two-vcpu-vm-is-slow/comment-page-1/#comment-74083 Scott Lowe Wed, 23 Apr 2008 17:48:11 +0000 http://lonesysadmin.net/?p=1234#comment-74083 I remember VMware preaching this back in the ESX 2.x days--as you probably do--so in some ways it's still surprising that more people aren't aware of the performance implications of vSMP VMs. It's a real challenge to get customers to understand that VMs shouldn't be provisioned in the same way they used to provision physical servers. Bob, thanks for bringing this issue to light (again). I remember VMware preaching this back in the ESX 2.x days–as you probably do–so in some ways it’s still surprising that more people aren’t aware of the performance implications of vSMP VMs. It’s a real challenge to get customers to understand that VMs shouldn’t be provisioned in the same way they used to provision physical servers.

Bob, thanks for bringing this issue to light (again).

]]> By: aharden http://lonesysadmin.net/2008/04/22/why-my-two-vcpu-vm-is-slow/comment-page-1/#comment-74081 aharden Wed, 23 Apr 2008 03:31:05 +0000 http://lonesysadmin.net/?p=1234#comment-74081 Like I assume you did, I found out about this the hard way. I first saw it when I tried to do 2-CPU VMs on two single-core hyperthreaded Xeons. (Back before I knew ESX better.) Nothing doing. Even on a four-core host it's questionable. On 8-core hosts I haven't found it to be a big issue (as long as 2-CPU VMs are the exception) but I completely agree that if you avoid mixing 1- and 2-CPU VMs on the same host there is less potential of a problem. Good points in your article. Like I assume you did, I found out about this the hard way. I first saw it when I tried to do 2-CPU VMs on two single-core hyperthreaded Xeons. (Back before I knew ESX better.) Nothing doing. Even on a four-core host it’s questionable. On 8-core hosts I haven’t found it to be a big issue (as long as 2-CPU VMs are the exception) but I completely agree that if you avoid mixing 1- and 2-CPU VMs on the same host there is less potential of a problem. Good points in your article.

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