[CentOS] Slow terminal response Centos 7.7 1908

Fri Jul 3 15:12:05 UTC 2020
Erick Perez - Quadrian Enterprises <eperez at quadrianweb.com>

Hey!
I have a strange condition in one of the servers that I don't where to
start looking.
I login to the server via SSH (cant doit any other way) and anything that I
type is slow
HTTP sessions timeout waiting for screen redraw. So, the server is acting
"slow".

server is bare metal. no virtual services.
no alarms in the disk raid

note: server was restarted because of power failure.

Some outputs from this server that is a mail server:
[root at correo ~]# top
top - 09:54:43 up 23:51,  2 users,  load average: 0.18, 0.23, 0.28
Tasks: 210 total,   1 running, 209 sleeping,   0 stopped,   0 zombie
%Cpu(s):  0.2 us,  0.1 sy,  0.0 ni, 99.8 id,  0.0 wa,  0.0 hi,  0.0 si,
0.0 st
KiB Mem : 32606084 total, 25106412 free,  5932244 used,  1567428 buff/cache
KiB Swap: 16449532 total, 16449532 free,        0 used. 26282624 avail Mem

**iostat**
[root at correo ~]# iostat -y 5
Linux 3.10.0-1062.12.1.el7.x86_64 (correo.binal.ac.pa)  07/03/2020
_x86_64_        (4 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.05    0.00    0.05    0.05    0.00   99.85

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               0.00         0.00         0.00          0          0
dm-0              0.00         0.00         0.00          0          0
dm-1              0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.05    0.00    0.05    0.05    0.00   99.85

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda              21.40         0.00       169.60          0        848
dm-0             21.40         0.00       169.60          0        848
dm-1              0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.60    0.00    0.05    0.45    0.00   98.90

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               1.20        16.80         0.00         84          0
dm-0              1.20        16.80         0.00         84          0
dm-1              0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.05    0.00    0.00    0.05    0.00   99.90

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               8.00         0.00       100.20          0        501
dm-0              9.00         0.00       100.20          0        501
dm-1              0.00         0.00         0.00          0          0

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.45    0.00    0.35    0.05    0.00   99.15

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sda               1.00         0.80         3.20          4         16
dm-0              1.00         0.80         3.20          4         16
dm-1              0.00         0.00         0.00          0          0


**dstop**
[root at correo ~]# dstat -cd --disk-util --disk-tps
----total-cpu-usage---- -dsk/total- sda- -dsk/total-
usr sys idl wai hiq siq| read  writ|util|reads writs
  1   0  99   0   0   0|  20k   17k|0.14|   1     1
  0   0 100   0   0   0|   0     0 |   0|   0     0
  0   0 100   0   0   0|   0     0 |   0|   0     0
  0   0 100   0   0   0|   0     0 |   0|   0     0
  0   0 100   0   0   0|   0     0 |   0|   0     0
  0   0 100   0   0   0|   0     0 |   0|   0     0
  4   0  84  11   0   0|2512k  228k|52.3| 123     2
 31   4  58   7   0   0|1912k 1026k|38.1| 132    23
  0   0  99   0   0   0|   0     0 |   0|   0     0
  1   0  99   1   0   0|4096B 3819k|22.5|   1   270
  0   0 100   0   0   0|   0     0 |   0|   0     0
 13   1  83   4   0   0| 148k 2304k|15.3|  18   214
  1   0  98   1   0   0| 140k  499k|9.70|  14     8
 26   5  69   0   0   0|   0  1260k|1.30|   0    46
 56   7  38   0   0   0|   0   204k|0.30|   0    12
 14  11  75   0   0   0|   0     0 |   0|   0     0
 22  10  68   0   0   0|   0     0 |   0|   0     0
 16  10  71   3   0   0| 192k   37k|14.0|  12     2
  0   0 100   0   0   0|   0     0 |   0|   0     0
  0   0 100   0   0   0|   0   152k|   0|   0     2
  0   0 100   0   0   0|   0     0 |   0|   0     0
  1   1  98   1   0   0|  16k 2569k|14.8|   1   207
  1   1  98   0   0   0|4096B    0 |1.10|   1     0
  1   0  99   0   0   0|   0     0 |   0|   0     0
  0   0 100   0   0   0|   0   600k|1.30|   0    51
  2   0  98   0   0   0|   0     0 |   0|   0     0
  4   0  96   0   0   0|   0     0 |   0|   0     0
  0   0 100   0   0   0|   0     0 |   0|   0     0



-- 

---------------------
Erick Perez
---------------------