virtualbox.org

Hi,

I am hoping someone has the magic answer for this since I have been working on it for a number of days now. I have a Windows 7 host with Ubuntu Linux as the guest. When I boot fresh the windows system and then start the linux guest all works great. If I run hdparm -t /dev/sda1 on the linux guest I get around 228MB/sec performace for the disk performace. That performace will be consitant for as long as the host does not go to sleep (hours and hours). If at any time I sleep the host and wake it back up the guest only gets 48MB/sec running same test. The only way to get back to the original disk rate is to shut the guest and host completely down and restart.

Ok now for all the version infomation:

I have tried it with two versions of virtual box (4.1.6 & 4.2.18)
I have tried it with two versions of Ubuntu (10.04 LTS and 12.04 LTS)

I have taken snapshots of all the services running both after clean boot and after exiting sleep. Nothing stands out.
System performace is idle
Guest has 4 cores assigned with 8 GB memory
Indexing of virtual box directories is disabled.
Host system is a Dell Precision quad core i7 (appears as 8 cores, 4 are hyperthreaded) laptop with 20GB of memory
I have searched for solutions and have not been sucessful.

Very wierd. The issue is I am doing a lot of compiling. With the good disk I/O builds takes 20 min and with the bad it takes 3 hours. It is a pain to have to shutdown everything and reboot each time I move my laptop around.

Any help would be very welcome..

Thanks!

Just an update. It does not appear to be a VirtualBox issue. I was able to reproduce the problem with winsat on windows. ON clean boot I get very fast SSD disk access and after waking from sleep, disk performace is 1/3 of what it was... ...

Any suggestions are still welcome...

Thanks!

Don't go to sleep?
Lots of coffee....

Just kidding. Sounds like a driver issue.