When I creating a 32-bit virtual machine with Cent OS 6.5 on Xen server 7.6, the following error is reported when the memory setting of the virtual machine exceeds 16G: the amount of physical memory allocated to this vm is greater than the total memory of its home server.
What is the maximum amount of memory that can be allocated to a 32-bit Cent OS 6.5 Xen server virtual machine?
The maximum number one can represent with 32-bits is 2^32-1, that is 4294967295. That is the maximum number of bytes a 32-bit processor can use from memory space. This equals to four gigabytes.
There is a mechanism called Physical Address Extension, which increases the addressable memory size from 32 bits to 36 bits, that is, 64 gigabytes.
I don't know if Xen server can implement virtual machines that have PAE enabled. PAE is needed if you want more than 4 GB memory for a 32-bit virtual machine.
