replication groups

[Eric Lambrecht]

Has anybody tried to build out any kind of 'replication groups' for 
mogilefs, where you can define something like "when keeping multiple 
copies of a file, make sure copy 1 goes somewhere in this set of hosts, 
copy 2 goes in this set of hosts, where those host sets don't overlap?"

I'm concerned that copies of a single file will end up stored on a set 
of machines that all share the same power strip... so if that strip 
goes, out, we're kind of fubar'ed for a while.

We're also hoping that if we could group the replications, this might 
help us for a move to a new datacenter - we'd be able to take down and 
move 1/2 of the machines while things continue to run on the remaining 
half (assuming you only keep 1 copy of everything).

Eric...
(p.s. - saw Brad's livejournal post on the device balancing... very nice...)