I had to force a restart of the backend pool.
Everyone will have failed over to their backup pool at 03:18 UTC
Pool is back up and working OK, hash rate heading back up to where it was before the restart.
Mine on

What backup pools do people recommend?
I suppose this doesn't make much sense, does it?
stratum+tcp://stratum.kano.is:3333
stratum+tcp://stratum.kano.is:443
stratum+tcp://stratum.kano.is:8080
A backup pool is ofcourse another trusted pool where your miners can jump on when kano's pool is down.
History shows that this does not happen much for long periods.
So seek a good pool as a second one and add that as the reserve one.
I allways have a 3th backup as well, but it happened only once that both the main pools went down in 8 years time