Exchange 2003 runs on SUN Microsystems and AMD 64 bit
Microsoft is going to release Exchange server 2007 only in 64 bit. They wanted to avoid existing limitation of existing 32 bit version of Exchange. Since Exchange more critical and heavily stressed application current 32 bit version pushes to its limits. Exchange 2007 64 bit will be better relief for those burning issues because it will easily exceeds current memory bottlenecks and help customers to go for consolidated server environment.
Since Exchange 2003 doesn’t have 64 bit version and couldn’t able to run on Windows 64 bit, because of that still people don’t thing about benefit of using 64 bit hardware. Since 64 bit hardware having backward compatibility to run 32 bit versions, it is worth while to invest for 64 bit hardware and do the migration to 64 bit applications after the release of Exchange 2007.
Recently I did a proof of concept at Singapore SUN labs about implementing Exchange 2003 and Windows 2003 R2 32 bit versions on SUN Microsystems servers and storage using AMD 64 bit opteron processors. Results were quit good I implemented two node Exchange active passive cluster with two dual processor servers and SUN storage. According to the calculation one server able handles nearly 5,000 users very easily and storage also performed well because disk utilization was 14% for 1000 users.
Still waiting to test on Exchange 64 bit; seems to be Exchange 2007 will be dominant mail server in future.