Unresponsive after being idle

[insats]

I'm using Ubuntu on VirtualBox on OSX host for web development. It works very well, except that whenever the computer guest OS has been idle for about 20-30 minutes, it becomes completely unresponsive for about 5-10 minutes. When it "wakes up" it's always quick and responsive, so it almost seems as some sort of deep slumber. When it's unresponsive, I can't SSH into the machine (i'm running it headless).

I can't find anything in the machine settings in regards to this, and I can't think of any settings in Ubuntu either that would cause this.

Does anyone have any idea what the reason could be?

[mpack]

Sounds like a power saving mode in Ubuntu. I would look at Ubuntu's configuration, not the VM settings.

[insats]

I've tried disabling the power saving functions in Ubuntu, but that didn't help. It's odd that it would even have power saving options. It's odd that Ubuntu Server would even have hibernation options since it's meant to host websites. Being idle is quite possible in that scenario.

[mpack]

Why is it odd that Ubuntu would provide power saving options? Most modern OS's do, AFAIK anyway.

[insats]

Well, I don't mean that it's odd that Ubuntu would have it. However Ubuntu Server is often used as a web server, and we deal a lot with ubuntu web servers. We use it for staging of websites (and that server is idle a lot, since it's not used in production) and have never come across this issue before, other than in the virtualbox environment.

[mpack]

I think a VM log file provides the only chance of casting light on this issue. Ideally the log of a session which has exhibited the problem. For what's needed see Minimum information needed for assistance.

[insats]

I had 4 different log files (VBox.log, VBox.log.1, VBox.log.2, VBox.log.3). I've attached 3 of them (I couldn't add more than 3 attachments to one reply). I think the one missing is VBox.log.