aaron-kelley.net

Running a few VMs in VMware Server 2.0.2 on Ubuntu Linux 10.04.  All works good most of the time.  Except when one of them, for whatever reason, needs to do a lot of disk I/O.  Then, all of the VMs grind to a halt until the disk activity is done.

Why is this?  I don’t know.  Obviously, if all of the VMs are using the same disk, there’s going to be some contention for disk access.  But, it seems that this slowdown is way worse than it should be.

Anyway, there is a solution to greatly reduce the impact of the problem.

Set all of your VMs to use only one CPU!  Yeah, that’s right.  I don’t know why that makes the situation any better.  Of course, there will be less CPU resources available for your VMs, but it’s worth it if they don’t stop responding whenever one of them decides that it needs to use the disk for more than a few seconds.

I got the idea from a post on the VMware Server forums and sure enough it worked fine for me.  Now the VMs are much more responsive while the disk is under load.  I don’t know if this problem also plagues VMware Server running on Windows, but chances are you can fix it the same way if it does.

VMware Server is a cool free product that you can install on an existing Windows or Linux system and run virtual machines in the background. While it’s built on VMware’s awesome virtualization technology, there are a few issues that make the current version of VMware Server (2.0.2) a little annoying to use.

Out-of-the-box, it can only be managed through the web interface. The web interface itself is not too bad, but if you aren’t accessing it from the same machine that it’s running on, it forces you to use HTTPS. This is great, of course, except something is wonky with the https implementation that is used (it appears to only support SSL version 2, for which support is disabled by default or outright removed from the current version of every major browser?). So, blah. I can’t manage my VMs remotely, which is one of the reasons why I’d like to use VMware Server in the first place.

Now, there are ways around this. You could set up an SSH tunnel or some similar network trick so that you could access the web interface without being kicked over to HTTPS. Or you could use Remote Desktop or a remote X application to access it using a web browser on the same machine as the server. These work for getting to the configuration pages, but I still had trouble trying to access the remote console (which relies on a browser plugin that seems a bit flaky).

There are lots of people complaining about both of these issues (flaky HTTPS and flaky remote console). Now, wouldn’t it be cool if there was a downloadable client that could manage said VMs without having to use the web browser?

(more…)