Working with virtual machines is easy and with the new XenCenter just a bit smoother than before. I created a new virtual machine called EX2007DC. Because XenSource now supports x64 guests, I installed Windows Server 2003 x64 edition and gave the virtual machine two virtual CPUs and 4GB of RAM. Here's the screenshot of the Overview tab of the virtual machine's properties:
The General tab provides more information about the virtual machine and allows you to change the VM Memory, number of VCPUs and the VCPU priority among other things. Note that the VCPU priority is a XenEnterprise feature and thus not available in XenExpress (free version). You can change the amount of memory and the number of VCPUs while the machine is running but of course, the changes will only take effect after a reboot. Here's a screenshot of the General tab:
It is a bit weird you can define more VCPUs than cores in the physical box. In the screenshot above I defined 4 vCPUs while the physical box (DL380 G5) only has one dual-core CPU. After doing that, the machine refused to boot and I had to revert to 2 vCPUs. Logical but the UI should prevent the user from making that choice.
You can note from the General tab's screenshot that the Virtualization: label reads Optimized. Like before, you have to install the XenSource tools in the Windows virtual machine to provide it with optimized drivers. The XenSource tools are on an iso (xs-tools.iso) that is automatically mounted when you select the option Install XenSource Tools from the VM menu in XenCenter.
Because I only have local storage on my server the virtual disks of my virtual machine are LVM logical drives. From the Storage tab, you can add storage to the virtual machine while it is running.
In the screenshot above you can see two disks. The second disk (extradisk) of 5GB was added while the virtual machine was running. Windows will pick up this disk (use Disk Management). As noted in the XenSource docs, the numbering of disks can be a bit different than expected. In my case, the second disk I added was numbered disk 0 in Windows and the first one was disk 1:
Note that you cannot hot remove WIndows disks.
The virtual machine's network settings can be seen from the Network tab:
Hot-adding and removing of virtual network cards is supported.
The Console tab lets you take control of the virtual machine and has several buttons for stuff like going fullscreen, undocking the window and so on. If you have installed the XenSource tools, there is a button that allows you to start remote desktop to the IP address of the virtual machine. There is also a dropdown list with ISO images to connect.
The Performance and Logs tabs:
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It's interesting to see that XenSource surpasses VMware when it comes to virtual machine abilities. VMware ESX's vSMP supports four virtual CPUs while XenSource XenServer supports 8. You can also assign more than 16GB of RAM and you can hot-add and hot-remove virtual network adapters. In most of our deployments these differences do not matter that much because most customers still use physical boxes when they need more CPU or memory resources. But interesting nonetheless.
