I agree that storage and replication are orthogonal issues. However, if a lump of storage is no longer a single point of failure then you don't have to invest (or gamble) quite as much to make that storage perfect.
Yes, that old maxim that each extra 9 in 99.99... reliability costs 10 times more.
Also a nice thing about replication is allowing controlled upgrades/changes to systems with almost no visible user downtime by controlled failing of all the masters off a particular machine. Nice.
Rob ---- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
