32bit Xen virtualized HA cluster?
This is my first post, of any kind, anywhere, ever... so I was a bit hesitant to start a new thread but was unable to find an existing thread that seemed appropriate. Also I realize I am fishing a bit with the 'Subject' line but I wanted to cast a broad net. If I missed an existing thread I apologize.
I am contemplating a new project and would appreciate some feedback from anyone with experience clustering 32bit processors.
My goal is to build a series of appliances each consisting of 2 nodes joined as an HA cluster. For scalability I intend for the appliances to be capable of being joined to create a larger cluster. I will be running Xen on top of the aggregate cluster with minimal single-service hosts running as domU guests. I am experienced with both Xen and HA clustering and have worked out most of the technical details. However, for efficiency, I am considering using mini-ITX boards with fanless C7 processors for the appliances and the C7 is a 32 bit processor. I am wondering if there is going to be an issue with the memory addressing limit inherent in 32bit processors once the cluster as a whole exceeds 4GiB of RAM. With the mini-ITX/C7 setup each node would have a roughly 1Ghz clock speed and 1GiB RAM so when I add my 5th and 6th node the total RAM will exceed the 4,294,967,296 address limit of a 32bit processor, however, at that point the cluster will have 6 processors available to provide addresses...
If anyone has created a 32bit cluster with more than 4GiB of RAM or is familiar with how Xen addresses memory when multiple x86 cores are available to it I would be greatly appreciative of feedback, barring a qualified response I will scrap together some old x86 machines and post a definitive answer. However, I would like to avoid the experiment if anyone can verify that it is a waste of time.
Thanks for your time, Joe