While Microsoft say you can (and support it under various configurations), running Microsoft Hyper-V Server 2008R2 off a USB keyfob doesn’t work that well – as we found out recently.
We’re building a new Hyper-V stack to trial a new hardware configuration, and to serve as a a base for our new Active Directoy ahead of Exchange 2010 and the uplifted hosting platform. The first server in the stack had the Windows image dropped onto a 16GB Kingston USB stick to be installed inside the server (this is a Microsoft support requirement – it has to be inside the server).
Building the server took nearly 3 hours (to the initial CTRL-ALT-DEL screen, not a great start) using the Microsoft supported deployment method, but once it was up and running it was surprisingly fast and booted from the USB stick to Windows in less than 90 seconds. We were impressed.
Our problems hit when we started to make changes to the base installation (such as installing updates via WSUS, or installing Core Configurator R2 for maintenance). It seems anything that reads and writes lots to the “disk” simply cripples the server in terms of response – a problem no doubt linked to the slow write speeds of the USB fob.
Installing Core Configurator R2 also highlighted another pitfall, it requires the DotNet Framework to function, and installing the DNF server role took what seemed like an age (15 minutes) compared to a server with a regular disk. This pitfall was again shown when we tried to install a backup agent.
Simple maintenance / install tasks, coupled with taking 12 hours Windows Update from our own WSUS server made us firmly believe the USB keyfob wasn’t up to the task in a production server.
Why? – Once the server was running, its performance was perfectly acceptable, infact impressive. Our concern comes from whenever we would have to update, perform maintenance or troubleshoot a failure. We believe the speed of the server would just be too slow during an outage or incident, and would prohibit a speedy return to service.
But ESXi works on a USB keyfob – True, and it works very well! However ESXi doesn’t have the same patching and update requirements of Windows Server. And when a new version of ESXi is released, the whole keyfob is updated in a single task, rather than reading/writing/updating lots of individual files. The same is true regarding extra drivers, applications, agents – they’re not installed into ESXi, but usaully are on a Windows server.
So what did we do? Took the USB keyfob out, and replaced it with a Solid State Disk. The server runs very very fast now, is still solid-state in terms of storage, and has been running our 2 dev Domain Controllers and a management server for nearly a week now without incident.
I’m sure the next version of Hyper-V Server will work better on USB (USB3 perhaps?), but for now, stick to disks…
Finally – For those of you that want to know, the server is based on a Quad-Core AMD Phenom II Black Edition CPU with 8GB of memory, dedicated Management, iSCSI and Customer Gigabit interfaces, all housed in a 4U chassis for future expansion. No optical drives, it doesn’t need one!
New Hyper-V server - better with a disk!
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