Linux virtual machine not recognizing memory

scottyp55 · 01-07-2010, 04:42 PM

I have a Red Hat 5.3 virtual machine that has 3GB memory. I just upgraded the memory to 4GB, however when I run free -m it still only recognizes 3GB. Is there something else I need to do?

Thanks,
Scott

scottyp55 · 01-07-2010, 06:59 PM

I found something that says I need to install the PAE kernel. I'm no linux expert. Is there an easy way to do this?

Thanks,
Scott

DrLove73 · 01-08-2010, 03:26 PM

You might need to install kernel-PAE-* (something like that) and use it instead of regular.

But, I think I read about similar problem on some Dell machines. What type and vendor is your machine?

scottyp55 · 01-08-2010, 04:18 PM

Thanks for the resonse. The Linux machine is a virtual machine on an ESX server. The ESX server runs on HP hardware. I tried the PAE kernel, but it was still only recognizing 3GB. Is there anything else I can try to get it to 4GB.

DrLove73 · 01-08-2010, 05:35 PM

What means "upgraded memory to 4 GB"??? I thought you just set the memory size in host guest system settings.

Another thing. Is ESX server capable to allow 4GB of RAm to the guest system? And does your host system seeing those 4 GB?

scottyp55 · 01-08-2010, 05:39 PM

Right. When I say upgraded the memory of the guest, I set it to 4GB from 3GB. The host has 32GB memory and sees it all. There are other virtual machines that are configured to use 4GB and can see it. The ESX server can give a guest up to 128GB of memory.

DrLove73 · 01-09-2010, 08:02 PM

Well, double check if ESX realy gave that virtual those 4GB, maybe try uping to 5GB to test?

scottyp55 · 01-12-2010, 11:51 AM

I ended up trying another PAE kernel and this time it worked. The memory is showing 4GB when I run free -m now.
One other question though... Now when I boot, I have to hit enter and select the new kernel or it defaults to the old one. Is there a way to change this so the new one is the default?

Thanks again to everyone for their help.
Scott

DrLove73 · 01-12-2010, 05:43 PM

go to /boot/grub/grub.conf and either change "default=0" (first "title" menu item to "default=1" (second "title" menu item) etc..., or cut entire section between "title" rows related to unwanted kernel, and pasted it somewhere on the bottom of the file.

BUT BACKUP THAT "grub.conf" FILE BEFORE ANY EDITING!!!