Recently I observed a relatively constant 7/8 (core) load on one of my servers. Looking with top, seems that CPU is constantly 75% waiting:
Tasks: 401 total, 1 running, 400 sleeping, 0 stopped, 0 zombie
%Cpu(s): 0.0 us, 0.0 sy, 0.0 ni, 25.0 id, 74.9 wa, 0.0 hi, 0.0 si, 0.0 st
Can't find anything obvious. System has 4x10TB drives out of which 4x9TB are allocated to a ZFS pool, the rest is mdadm RAID10. /proc/mdstat shows no check/rebuild, for ZFS I'm not sure exactly where to look at.
I did an apt update ; apt upgrade (Debian 10.7), hanged for already 30minutes at:
Unpacking linux-image-4.19.0-14-amd64 (4.19.171-2) ...
Progress: [ 33%] [#######################################################################................................................................................................................................................]
The applications seem to run fine other than that. I was thinking of a reboot, since it has almost 300d uptime but now with apt upgrade hanging I really don't know how to proceed.
Any suggestions?
