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I have a 16 core machine having 8 GB of RAM running windows 2008 I installed a virtualbox on it and installed windows 2008 64bit os and allocated 4 GB RAM to it . A Mysql database was installed on the guest OS for my applicaton to use it. The activity of Mysql database is pretty high.

Unfortunately the Host OS shows a Physical memory usage of 89% which is totally unacceptable. Is there any configuration that i can do inorder to reduce the Physical memory usage of the host OS ?

If I sum all the process listed in the task manager it doesn't go above 2 GB

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migrated from Mar 14 '11 at 3:23

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Which processes are at the top of the list for high memory usage? – Randolf Richardson Mar 7 '11 at 10:08
If I sum all the process listed in the task manager it doesnt go above 2 GB – Anuj Mar 7 '11 at 10:09
7.12 would be 89% so if you have 2GB and change plus the 4GB you are very close to 89% and I would not be surprised if it spikes to 89% regularly, sounds like you just need some more RAM, or need to allocate less to the VM. – Not Kyle stop stalking me Mar 7 '11 at 16:02
up vote 1 down vote accepted

You reserved 4GB out of your 8GB for the VM. Even if your guest isn't using it, that allocated memory is unavailable to your host while the guest is running. That means take 50% off the top when reading your RAM use. The remaining 39% translates to 3.12GB. That sounds about right for your operating system + an active, running server application. If the sum doesn't add up, make sure you're viewing processes from all users, and not just your user.

I have two other observations:

  • 8GB is way underprovisioned on RAM for a 16 core server. You want at least 1GB per core, including hyper-threading if applicable. More would be better — depending on what you're doing, maybe a lot more.
  • In the general case, what's wrong with 89% utilization? You don't want RAM just sitting there idle. If it's not in use, it's wasted. I understand if you're still in testing and you expect your final load to be much higher, but I just want to make sure you're expectations for utilization are where they should be.
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4GB plus 2GB is close to 89% usage. Install more than 8GB ram on that 16-way would be my advice.

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89% of 8 GBs is slightly more than 7 GBs. Perhaps there are temporary memory allocations which aren't being tracked with specific processes, or disk cache is in use (which would make sense given high activity in MySQL).

Make sure you're using the 64-bit versions of MySQL and other such software (I'm assuming, of course, that MySQL is available for Windows as a native 64-bit program).

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