Maximum number of CPUs

[mva]

Hi all,

What is the maximum number of CPUs supported by current stable PVE 1.8 kernel(s)?
AFAIK stock kernels of Debian Lenny are configured to support only 32 CPUs.

- Mikael

 

[tom]

in the moment I have no answer to your question but did you reach the limit? btw, we do not use the Lenny kernel, in the moment our 2.6.32 kernel is already based on Squeeze.

 

[mva]

After some deeper investigation I think I found the answer:

# cat /boot/config-2.6.32-4-pve | grep CONFIG_NR_CPUS
CONFIG_NR_CPUS=512

I'm planning to install Proxmox on a 48 core monster, but the limit of 512 is more than enough

 

[tom]

I would love if you report a success story, including some details of your hardware setup.

btw, I just checked our kernel for the upcoming 2.0 release:

cat /boot/config-2.6.32-6-pve | grep CONFIG_NR_CPUS
CONFIG_NR_CPUS=4096

so you can safely invest in bigger boxes

 

[mva]

I would love if you report a success story, including some details of your hardware setup.

I hope the story to be a success one, but yes, I'll let you know.

btw, I just checked our kernel for the upcoming 2.0 release:

cat /boot/config-2.6.32-6-pve | grep CONFIG_NR_CPUS
CONFIG_NR_CPUS=4096

so you can safely invest in bigger boxes

I've scheduled the installation to somewhere in the middle of the next month.
Being able to do that with a brand new 2.0 version would be a really pleasant surprise

 

[jekader]

Heh, I've also been waiting for PVE 2.0 in hopes I'll be installing it on a 2x6-core xeon+HyperThreading server, but it looks like I'll stick with 1.8 for now.
BTW, even the RHEL4 kernel worked with a similar configuration without problems using all the 24 cores, although in my case it's less than 32.

 

[mva]

I would love if you report a success story, including some details of your hardware setup.

Proxmox installation went eventually fine, but I ended up into an unsupported configuration in the PVE point of view. (PVE 1.8 on top of Debian Squeeze)
System seems to run stable with 2.6.32-6-pve kernel.

# cat /etc/debian_version 
6.0.2

# pveversion -v
pve-manager: 1.8-23 (pve-manager/1.8/6533)
running kernel: 2.6.32-6-pve
proxmox-ve-2.6.32: 1.8-41
pve-kernel-2.6.32-6-pve: 2.6.32-41
qemu-server: 1.1-31
pve-firmware: 1.0-13
libpve-storage-perl: 1.0-19
vncterm: 0.9-2
vzctl: 3.0.28-1pve5
vzdump: 1.2.6-1
vzprocps: 2.0.11-2
vzquota: 3.0.12-3
pve-qemu-kvm: 0.15.0-1
ksm-control-daemon: 1.0-6

# pveperf 
CPU BOGOMIPS:      220821.82
REGEX/SECOND:      892761
HD SIZE:           4.58 GB (/dev/mapper/vg0-root)
BUFFERED READS:    256.13 MB/sec
AVERAGE SEEK TIME: 4.12 ms
FSYNCS/SECOND:     2019.96

Specs of the hardware: Dell PE 815; 4 x 12 Core AMD Opteron 6176, 128GB ram, Dell PERC H700 raid controller, local disk storage 1.2TB in 4xSAS10k RAID10
The good thing is that we use this box in a test environment thus maximum stability is not required. But anyway the plan is to switch onto PVE 2.0 beta as soon as it's available.

 

[spirit]

i'm running 2x r815 (48cores) since 1 year, and it's running very fine and stable with proxmox.

Last kernel release is very great in proxmox 1.9:

- 64 vcpus by vm (try to edit manually your vm config, because gui limit to 16)
- transparent hugepage
- vhost with virtio nic is working fine. (i had tested up to 5gbit/s)
- ksm support