My CentOS server (CentOS release 5.10) using Kibana has collected
Filesystem Type Size Used Avail Use% Mounted on
/dev/hdb ext3 25G 3.6G 20G 16% /kibana
since July 25th, 2014
but I'm only grabbing 3 hosts via (r)syslog at the moment.
One of those hosts is our mail server and it consumes the most amount of disk space on the kibana host.
Either Ubu or CentOS, it's a matter of preference, I guess.