On Tue, Nov 18, 2008 at 3:58 PM, Filipe Brandenburger filbranden@gmail.com wrote:
Hi Rudi,
On Tue, Nov 18, 2008 at 02:13, Rudi Ahlers rudiahlers@gmail.com wrote:
...which can't take a lot of load... ...the machine sky rockets at some times...
The problem you have is that the Load Average is too high?
If that is indeed your problem, there is no way that this can be a memory or CPU issue, since those would cause crashes and not high Load Average.
If what you have is high Load Average, check this:
- Your machine has 8GB RAM. Are you using the 64-bit version of
CentOS? There would be an overhead in using a 32-bit PAE version on a machine with more than 4GB, last time I tried it (some years ago) the overhead was big enough to make a difference in the server's performance.
- Your machine has SATA. If you don't use the correct SATA settings on
the BIOS, CentOS may use it in a backwards compatible mode and you will not get enough performance out of it (see previous posts on problems on SATA and on AHCI). If that's the case, changing the BIOS settings might make a huge difference, but beware that if you do your machine may no longer boot with the OS you installed right now. Better thing to do would be to reinstall it once you found the right setting.
And next time, please state your problem clearly ("high Load Average") instead of jumping the gun and saying you have a CPU or RAM issue which does not seem to be the case here.
HTH, Filipe _______________________________________________
Hi Flippie,
I have checked the BIOS settings, purely cause the new HDD was installed on a machine withou AHCI settings, so I had to change the settings in the BIOS to nativ IDE mode (the only other mode this motherboard supports).
The reason why I'm suspecting the MB / RAM / CPU is that I already swapped the HDD's out, and reinstalled CentOS - first it was x64, now it's i386 (well, i686 as per uname -a). The only serivce that runs on the host node is HyperVM (which include the XEN tools, PHP, Apache, MySQL.
I have the exact same setup on a few other machines, using Gigabyte motherboards + 4GB RAM. Other than that, the HDD's are the same, the OS is the same, and HyperVM is the same. I basically run yum upgrade once a week on all the machines. The only difference is this one has an Intel DG35EC motherboard with a Q9300 Quad Core CPU on it, which is supposed to be more power efficient than some of the Core 2 Duo CPU's on the other machine.
As a matter of interest, all 5 Virtual Machines have been running on a Gigabyte motherboard + i6450 CPU + 4GB RAM since yesterday, and it's very very stable.
So, my thinking is, it's the motherboard. It could also be the RAM, but I'm not 100% sure yet. The machine had 4GB initially, and then I added another 4GB hoping the problem would go away, but it didn't.