services run on 1 machine only. you can make a backup but all I know is that there is always 1 machine running (at least) 1 IRCd and 1 Services Deamon (if the IRC network is running services)

services are nothing more then bots with IRC-oper rights really... all using the same database

Code:
[18th?10:17:22] » (MAP) <*********> palm.irc.*********.net               (Users:   32)  (33%) [*********link6.15.2]
[18th?10:17:22] » (MAP) <*********> |-lefruitdemonde.irc.*********.net   (Users:    4)  ( 4%) [*********link6.15.2]
[18th?10:17:22] » (MAP) <*********> |-grolsch.irc.*********.net          (Users:   23)  (24%) [*********link6.15.2]
[18th?10:17:22] » (MAP) <*********> `-kriek.irc.*********.net            (Users:   30)  (31%) [*********link6.15.2]
[18th?10:17:22] » (MAP) <*********>   `-brouwerij.*********.net          (Users:    6)  ( 6%) [PTlink.Services2.21.3]


as you can see on this /map there are 4 IRCd's, running on 4 different machines, on 1 (kriek) the services are also running (in this case it's nickserv/chanserv/the rest).

this means if kriek would split the services will be on the other side of the split if your not on kriek, and can't be reached untill relinked.

servers communicate realtime with eachother, and there is only 1 services deamon so that doesn't have to sync it's data

If it ain't broken, don't fix it!