Dell M620: Xen-Kernel CPU-Limits

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cyon_technik

Dell M620: Xen-Kernel CPU-Limits

Post by cyon_technik » 2014/05/26 09:16:13

Dear CentOS-Community

I set up a Dell PowerEdge M620 Server with CentOS 5.10 x86_64. The M620 has two Intel Xens with 10 Cores and HT, so in summary 40 logical CPU-Cores.
My problem is, that the default xen-kernel 2.6.18-371.8.1.el5xen initialize only 32 CPUs on boot. If if run the default kernel 2.6.18-371.8.1.el5 (without xen) i got all 40 CPUs.

The CentOS 5 x86_64 limitations about CPUs are 160 (http://wiki.centos.org/About/Product) so this is not the problem.

Is there any kernel parameter i need to attach on the xen kernel or something else?

Thanks in advance.

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TrevorH
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Re: Dell M620: Xen-Kernel CPU-Limits

Post by TrevorH » 2014/05/26 15:11:50

http://xen.1045712.n5.nabble.com/kernel ... 09451.html seems to say that the underlying xen kernel will see them all - which can be verified by running xm dmesg or more exactly xm dmesg | grep -i brought. It's the guests under it, including the Dom0 which is a special sort of guest, that are limited to 32 cpus each.

Check xm top on the Dom0 and I suspect it will say 40 cpus at the top right hand side.
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cyon_technik

Re: Dell M620: Xen-Kernel CPU-Limits

Post by cyon_technik » 2014/05/27 07:44:00

Thanks a lot! This is exactly what i was looking for.

Greetings from switzerland.
Christian

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