Ubuntu 13.10 Server Intermittently Slow on OS X 10.9

[Greg Williams]

I've been running VirtualBox on a Mac Mini running OS X 10.9 for about a month, and performance has generally been quite good. I have one guest running Ubuntu Server 13.10 in headless mode. I became aware of performance issues when I started running WordPress on the guest. Sometimes performance is very good, with complex pages loading in a second or two. Other times, pages take take 30 seconds or more to load.

It seems as though if I'm logged into the Mac, either via VNC or at the physical console, performance of the Ubuntu guest is good. If I'm not logged-in, performance is bad. Logging in via SSH seems to have no effect.

I'm launching the guest with the following command from within an SSH session:

VBoxManage startvm "UBS01" --type headless

Note that I'm not using sudo, or otherwise running it as root.

Neither CPU load as reported by top on the guest nor the host ever seem to show any signs of significant load, nor any obvious differences between good performance and bad performance states.

Any suggestions on how to get this guest to run well consistently?

[socratis]

Although not en expert on this (not even advanced user), here are a couple of things that you can try out:
- Check out the metrics option in the 8.33 section of the manual.
- You don't have to sudo. In fact, you should not.
- Have you checked the WordPress and/or Ubuntu forums for similar issues?
- Have you tried running it non-headless? What does it look like?

[Greg Williams]

Socratis,

Thanks for your help.

• I've reviewed the 8.33 section of the manual covering metrics. This doesn't seem to offer any information I haven't already analyzed via tools such as top running on the host and guest.
• I didn't think I had to (or wanted to) sudo, so I'm glad you agree.
• I haven't spent much time looking at the Ubuntu or WordPress forums on this subject because the performance problem seems to apply to the guest as a whole, not just WordPress. For example, whenever performance is bad, it takes a long time to get output from basic commands such as ls and top. This is so even if there are no ongoing queries to Apache/WordPress.
• I get good performance in non-headless mode, which is expected: I have to be logged into the Mac's console in order to run in non-headless mode, and I already know I get good performance whenever I'm logged in at the Mac's console.

Thanks again.

Greg

[Perryg]

Share the guests log file ( as an attachment )
As well as VBoxManage showvminfo <name> --details

[Greg Williams]

Here you go.

[Perryg]

VirtualBox VM 4.3.2 r90405 darwin.amd64 (Nov 1 2013 15:42:35) release log
00:00:08.542130 AIOMgr: Host limits number of active IO requests to 16. Expect a performance impact.

Only warning I can find and it can be a big one as far as performance goes. Is there anyway to increase the number of requests on a Mac?

I also see you are running 4.3.2 and 4.3.4 is out that has fixed a few regression issues. Not sure if it affects your issue but worth trying.

Another thing that would be great to see is a snag of the log file while you are seeing the slow down, as well as the IO report from the guest when this is happening.

I use iotop