Thursday, March 12, 2009

USB in ESX - How?

Since we brought it up and since I feel like a slacker for not posting in several weeks I thought I'd share my experience on managing USB devices in an ESX environment. In my previous post I mentioned a posting about connecting USB devices to ESX hosts and the many different ways for doing that in both a temporary and permanent fashion. I've never had much need for temporary connection but for a rock solid permanent solution I highly recommend AnywhereUSB by Digi - website.

Priced at just a couple of hundred dollars you are able to assign one of these an IP (or DHCP which I don't recommend), install the supplied software on your guest VM, plug in your USB device and you're up and running. Ok, so in all honesty here are some gotchas and other things to keep in mind:

1. One AnywhereUSB device to one operating system at a time. You can mix and match between physical and virtual as long as they have the provided client and drivers but only one server can talk to one of these guys at a time. This also means that even though it has 5 USB ports in it you can not map them to individual servers. Hopefully someone from Digi will correct me on this but that's just the way it is.

2. Give it a static IP. It makes it so much easier to track it down and to keep track of which one is which. If you purchase multiples of these you had better label the unit as well. You'll thank me for this one.

3. Follow the instructions for installation. I know you're gitty to have this device but if you skip a step you'll be sorry. Refer to #5.

4. Just because you have a gigabit network, you're limited to the speed of the AnywhereUSB device. I vaguely recall seeing that you may get USB2 speeds of 400mbps but I have not seen that as the case in production. If you have a 100Mb network then you know what your cap is already regardless.

5. Make sure you load the Windows generic drivers on your guest VM. ESX does not present USB to the VM, and you're not adding it to your VM's settings unless you've been doing some unsupported hacking, so the generic drivers were not installed when your OS was installed. In order to do this you'll need to copy the usbd.sy_ file from the \I386 directory of the Windows CD to the \system32\drivers directory and CHANGE THE FILE EXTENSION to usbd.sys. Reboot and then install the software. If you miss this step you'll be sorry.

6. I found it quite refreshing the first time I installed one of these guys and had the presence of mind to try it out first on a test server a snapshot before taking the first step. Always a good practice when installing something new for the first time.

7. You have to reboot at least once to use an AnywhereUSB device. That should be all though. Refer to #5

If you've kept these things in mind and follow the instructions you'll have many happy years of giving your VMs access to critical USB devices without unsupported hacking or sacrificing VMotion.

Original Post - VMETC.Com

Digi - AnywhereUSB Website

USB in ESX - Why Not?

I was recently talking with a friend about the beauty of USB devices in Workstation and we quickly began talking about the difficulties of USB devices in ESX. This is a problem I had already tackled some years ago with AnywhereUSB but earlier this evening I found a post discussing USB connectivity to an ESX hosted VM and felt it time to talk about it with you.

In the post the author describes several means for connecting USB devices in both temporary and permanent scenarios. I personally have never had much need for one time connectivity but since many of our applications require USB dongles for their license managers it's safe to say that connecting through the host or through RDP just won't do as a permanent solution. This is especially true as virtualization continues to branch out into the desktop arena where USB devices are more than just a pretty face, they're often a non-negotiable requirement.

While the post was extremely helpful one of the items that I feel the author failed to discuss is why VMware would continue to not support USB connectivity to guest VMs from their ESX hosts. Why wouldn't they indeed?

My immediate belief is that like most things it is for our own protection. Just imagine how upset your management, or you if you are the management, would be if DRS did not properly balance your resources, HA did not restart your server upon a failure, or you were not able to put a machine into maintenance mode due to a USB device preventing Vmotion because of a device associated to a single host. I know I wouldn't want to tell the boss that the thousands of dollars I fought hard for to purchase these features were all done in because of a USB dongle. Note: I have not yet tested this scenario but it seems reasonable given the results I've seen from having VMDKs and ISOs on local storage.

The greatest strength of VMware over its competitors is that they control the hardware and control the drivers that the VMs see. They have worked hard on their hypervisor to make these features available and I'm pretty sure that they won't open their arms to USB devices on the host anytime soon. After all, there are clearly many different options out there that solve this issue. Where's the benefit in complicating their already growing datacenter OS further?