Hello!
There was a grrrit-wm outage for a few hours earlier today. This was caused by the link between our tampa datacenter (where toollabs mostly lives) and our eqiad data center (where gerrit lives) (see preliminary report on http://lists.wikimedia.org/pipermail/labs-l/2013-September/001678.html).
It is back up now, and I'll see if I can find ways of figuring out when a ssh connection to gerrit is 'hung' (but not terminated).
Thanks!