We were hit by the leap second bugs in the Linux Kernel. I've written up my experience on our technical blog.
http://blog.fastmail.fm/2012/07/03/a...aping-seconds/
Original post here below:
We're having a really bad day of crashing spam scanning servers. Mostly users won't see any issues, apart from slight delays (5-10 minutes) on incoming emails when one of the servers crashes.
Interestingly, it seems to not just be us - other departments in Opera are having failures too. At first we suspected the specific hardware, but we've had crashes on other equipment too. It might be a rough day.
On the plus side, our robust failover systems are working fine
The process for dealing with a failed server is now so easy I can do it from my phone in ~30sec.