Symptoms
The commands uptime, sar, top etc., show very high CPU usage, but no process is shown to be causing it.
top - 14:27:15 up 94 days, 11:29, 2 users, load average: 103.12, 103.15, 103.14
Tasks: 664 total, 1 running, 659 sleeping, 1 stopped, 3 zombie
%Cpu(s): 0.3 us, 0.3 sy, 0.0 ni, 99.3 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem : 36906356 total, 4912532 free, 2565540 used, 29428284 buff/cache
KiB Swap: 6160380 total, 5913596 free, 246784 used. 32704200 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
26702 root 20 0 160672 2932 1632 R 3.2 0.0 0:00.29 top -c
25892 nobody 20 0 0 0 0 Z 0.6 0.0 0:00.23 [httpd] <defunct>
10 root 20 0 0 0 0 S 0.3 0.0 457:02.59 [rcu_sched]
35 root 20 0 0 0 0 S 0.3 0.0 47:00.69 [ksoftirqd/5]
Description
One cause of this issue could be wrongly configured NFS mounts.
# mount | grep -i nfs
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw,relatime)
1.2.3.4:/home/5.6.7.8/mydomain.example.com on /home/example/mydomain-data type nfs (rw,relatime,vers=3,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=1.2.3.4,mountvers=3,mountport=20048,mountproto=udp,local_lock=none,addr=1.2.3.4)
Connection errors are visible in dmesg:
# dmesg | tail
[8160377.566380] xs_tcp_setup_socket: connect returned unhandled error -107
[8160437.726473] xs_tcp_setup_socket: connect returned unhandled error -107
[8160498.894449] xs_tcp_setup_socket: connect returned unhandled error -107
[8160560.062429] xs_tcp_setup_socket: connect returned unhandled error -107
[8160621.230448] xs_tcp_setup_socket: connect returned unhandled error -107
[8160682.398430] xs_tcp_setup_socket: connect returned unhandled error -107
[8160743.566515] xs_tcp_setup_socket: connect returned unhandled error -107
[8161241.935327] xs_tcp_setup_socket: connect returned unhandled error -107
[8161303.102432] xs_tcp_setup_socket: connect returned unhandled error -107
[8161820.430441] xs_tcp_setup_socket: connect returned unhandled error -107
Workaround
Fix the connection issues with NFS.
Please note that we do not test functionality with NFS and that it is unsupported. See our system requirements:
Note:
We only develop and test cPanel & WHM on filesystems that support flock. Some network filesystems (for example, NFS) may require additional configuration in order to function properly. However, these configurations are difficult to implement successfully and we do not support them.