RVM Log and Metadata Sizes

[coda]

Hi,

Is there an official limit on RVM log and metadata file sizes? I set my 
log size to 2GB in order to be able to handle files up to 2GB. Ideally, I 
wanted to be able to handle a FS up to 0.5TB, so I wanted to make a 
metadata file of about 16GB. The biggest I've managed to get to work is 
4GB, otherwise things fail with an error. Does this sound about right?

I am using a file, rather than a partition. Am I correct in guessing that 
mmapping the file only maps it into virtual memory without actually 
requiring that much RAM+swap in the system (unlike when using a 
partition)?

On a related note, are any of these limits (file/log/metadata) 
architecture dependant? If so are there any issues with having an 
x86-64 and an IA32 node in the same replicated cluster?

Thanks.

Gordan