32 vs 64 OpenVZ Template

[matthew]

What is the difference between using one or the other? I imagine since this is shared kernel under the hood the 32 version is going to be running on a 64 bit kernel? Why would you choose a 64 bit version? Can I give a 32 bit VPS more then 4 GB of RAM and will is use it? Reason I ask is I have a couple CentOS 5.x 64 bit physical boxes that I want to move too OpenVZ containers. They are quite memory hungry. My box running Proxmox has 8 cores, 64GB of RAM and a large RAID array to share so it should have plenty to go around for now. Thanks.

 

[gkovacs]

On Proxmox VE, the host kernel is 64-bit, and you have a choice of running 32-bit or 64-bit containers. 32-bit guests can only use 4GB of memory address space AFAIK. OpenVZ is the most processor and memory-efficient virtual environment there is, since the kernel and many parts of the system are shared between containers.

On a box with enough memory, you should go for 64-bit containers as they provide better performance (especially with Apache and MySQL), and are also more future-proof should you find the need for more than 4GB of RAM.

Our general experience with OpenVZ is that you run out of CPU or disk IO much sooner than RAM.