>About four years ago when I first started managing this AFS cell we tried
>using three database servers, but to send a new copy of the databases from
>the master to the slaves took 40 minutes or so. FTP was faster than
>whatever mechanism AFS was using to do the updates.
It's my understanding that Ubik write performance decreases as you add
database servers (which it really shouldn't, but from my looking at
packet traces it seems there's some inefficiency in the rx_multi calls).
However ... once you've elected a new database master, you just send
incremental updates, and presumably you don't do that _that_ often (but
I can see why 40 minutes is way too long for that if there were occasional
glitches). I sometimes wish Ubik was smart enough to look through the
database log and only send the changes since your last committed version
when a reelection happens.
--Ken
