in reply to Google like scalability using perl?
You might also try memcached, as suggested above. The combination of memcached and mod_perl performs better than I expected.
For doing a large batch job by farming work out to lots of nodes, the trick is to use something like Amazon's Simple Queue Service, which keeps the work from overlapping. I don't know of a perl module that implements this, so if your code has this feature it would make a great CPAN module by itself.