Due to until now unknown reasons the server which holds the Jabber services crashed four times in the last not even two hours. From one second to the other the ejabberd processes took every resource they could get, and even more. 8 gigs of RAM and 8 gigs of swap, everything gone. Plus a lot of CPU load. The machine was loaded that “top” refreshed just every 5 minutes and in the end just a hardware reset helped to reboot the machine.
For the tech geeks:
top – 19:56:21 up 31 min, 1 user, load average: 22.86, 13.11, 8.71
Tasks: 240 total,  3 running, 231 sleeping,  0 stopped,  6 zombie
Cpu(s): 1.4%us, 5.8%sy, 0.0%ni, 12.4%id, 80.3%wa, 0.0%hi, 0.1%si, 0.0%st
Mem:  8190900k total, 8138972k used,   51928k free,     796k buffers
Swap: 8393848k total, 7276916k used, 1116932k free,   42404k cachedPID USER     PR NI VIRT RES SHR S %CPU %MEM   TIME+ COMMAND
3239 ejabberd 20  0 15.7g 6.0g 460 S  23 76.7  3:06.65 beam.smp
We are looking into this issue. Maybe a severe bug with ejabberd, maybe a DoS attack. We don’t know, yet.