I recently had an issue with vmware’s vCenter where all virtual machines and hosts were showing as “Disconnected”. Nothing could be done in the control panel, but it functioned otherwise. Doing a quick search online, I didn’t see many results, so I restarted the instance, hoping the issue would self-resolve. However, the instance didn’t come back up after a restart. I explain how I resolved the problem, and give general troubleshooting tips to find problems.
I recently got another eight solid state drives in for my second Poweredge R710 (“Lucid”), but was getting a “Virtual disk creation failed!” error when creating the array. Even after wiping the drives of partitions and data, I was still getting the error.
Hypervisors generally allow creation of virtual devices (sound, USB, network), which will work in most cases. However, if you need more control over the device or more options than the stock virtual device gives, you are going to find yourself stuck. To get around this, PCI passthrough is used to pass a raw device (such as a sound card, RAID card, video card, etc) directly into a virtual machine. This gives unfettered access and to the virtual machine, it is treated as if the hardware were directly connected. In the guide below, I explain how to pass through PCI and USB devices to Xen Cloud virtual machines.