I have several servers running Ubuntu 16.04 that suddenly have accounts-daemon
process utilizing 100% of their CPU.
The first time it occurred 3 weeks ago, I moved /var/log/wtmp
and re-created it, which immediately solved the problem.
That was the first solution I came across, another one was to disable these wtmp
logs in proftpd.conf
.
Are there any risks associated with doing that? Will it solve the problem?
Best Answer
I was having the same issue with accounts-daemon taking nearly 100% CPU on a 16.04 Ubuntu.
In short, the root cause were serial console agetty-s, continously (i.e. a few times a minute) restarted by systemd.
(I acknowledge not exactly answering Sam's main question -i.e. disabling wtmp completely-, but other people in trouble are likely to find this page - as I did)
==
Details for the curious:
[6] [30697] [tyS2] [LOGIN ] [ttyS2 ] [ ] [0.0.0.0 ] [Sun Dec 30 07:19:34 2018 CET]
[6] [30698] [tyS1] [LOGIN ] [ttyS1 ] [ ] [0.0.0.0 ] [Sun Dec 30 07:19:34 2018 CET]
[8] [30698] [tyS1] [ ] [ttyS1 ] [ ] [0.0.0.0 ] [Sun Dec 30 07:19:44 2018 CET]
[8] [30697] [tyS2] [ ] [ttyS2 ] [ ] [0.0.0.0 ] [Sun Dec 30 07:19:44 2018 CET]
[5] [30707] [tyS2] [ ] [ttyS2 ] [ ] [0.0.0.0 ] [Sun Dec 30 07:19:44 2018 CET]
[6] [30707] [tyS2] [LOGIN ] [ttyS2 ] [ ] [0.0.0.0 ] [Sun Dec 30 07:19:44 2018 CET]
[8] [30707] [tyS2] [ ] [ttyS2 ] [ ] [0.0.0.0 ] [Sun Dec 30 07:19:48 2018 CET]
Indeed, there were some serial consoles somehow activated (systemctl | grep ttyS.*service), which I removed by commands like "systemctl disable getty@ttyS2.service" (I have no idea why and how these serial agetty-s were activated, but this is a very old system.)
wtmp immediately stopped growing and accounts-daemon disappeared from top output. I guess accounts-daemon only activates for new wtmp records, so even if it is inefficient, it rarely runs now.
Cheers: Arpad