Performance problems with FreeBSD guests

[jpbergamin]

Dear VMWare-Users

We are currently evaluating VMWare to replace our XenServer infrastructure, because FreeBSD >= 7 does not run on XenServer anymore.

Our main use case is to virtualize our build and test hosts running FreeBSD 6 and 8 (i386 and amd64). After installing some FreeBSD guests, we face performance problems. The host is running ESXi 4.1 on a machine with two dual-core AMD Opteron CPUs and 8GB RAM (which should be sufficient for the first tests).

Building our software on a FreeBSD guest takes much :smileyalert: longer then on a physical machine.The VMs throttle their CPU-usage down to a couple dozens of MHz in idle state and it takes quite a while that the CPU usage is increased when a build is started on a VM, although no other VMs are using any noticeable CPU ressources. When starting a build on a second machine it takes even longer until its CPU usage reaches an acceptable value. When starting a build on a third machine, this machine never gets more CPU usage then ~500 MHz assigned and this build takes ages.

Working with such a FreeBSD guest feels very "lame". You login in with SSH, want to start a build or do this and that and it takes very long until the machine "wakes up" and acts acceptable. This is also reflected in the CPU-usage that is assign to this machine which is increasing only slowly.

It is normal that it takes this long until a VM gets useful CPU ressources assigned, although enough CPU power would be still available? Can the hypervisor be configured to assign CPU usage much more aggressively? In our usecase we want a guest to get as much CPU ressources as possible - at a sudden. When I login via SSH and type "make", all available CPU power should be available at a sudden.

Any hints or tips how to achieve this?

Thanks for sharing your thoughts

James

[golddiggie]

We need to know how the VM's are configured before we can even think about giving suggestions... How many vCPU's do you have allocated per VM? How much RAM do you have allocated per VM? Do you have any reservations, or limits set on the VM Resources settings? What are you using for storage for the VM's to reside upon? What are the AMD processors in use? Is the server actually fully supported for ESXi 4.1 (on the VMware HCL)?? Is this an actual server or a glorified desktop system?

Personally, I wouldn't use amd processors in an ESX/ESXi host server. I've had far better results with Intel Xeon's (quad cores and better). IF I was forced to use amd processors, I'd go with at least a dual, quad core configuration (same as I do with Xeon's)...

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