Ubuntu began to freeze, are there any ideas in which direction to dig?

Question

ubuntu

during work, the system began to freeze, not for a long time, but it began to annoy, googled, but nothing came up.

Answer 1

Install HTOP and check which modules are loading the system.

sudo apt-get install htop
sudo htop

PID - process ID.
USER - the owner of the process.
PRI - current priority (affects the processor time allocated to the process, the default value is 20; the lower the priority, the more time is given to the process, therefore it runs faster).
NI - the amount of priority change relative to the value of PRI (keys F7, F8).
VIRT is the total amount of virtual memory used by the process. Includes: code area (CODE), data (DATA), shared libraries (SHARED), and pages moved to swap memory area. If an application requested the kernel to allocate 100 MB of memory to it, and uses only 5 MB, this column will still show the number 100.
(CODE - the amount of memory containing the executable code of the process.
DATA - the amount of memory occupied by the data used by the process during execution.
SWAP - the amount of memory used by the process, but moved to the swap area.)
RES - the amount of resident (not moved to swap) memory in kilobytes. If the application requested the kernel to allocate 100MB of memory to it, and uses only 5 MB, then this column will show 5. But there are two nuances here:
a) RES does not show how much data was moved to swap,
b) part of the RES memory can be shared.
SHR - the amount of shared (shared) program memory in kilobytes, i.e. memory that can be used by other applications.
S is the state of the process:
S is the so-called sleep state;
R is the state of execution;
D - waiting state.
CPU% - CPU usage as a percentage.
MEM% - percentage of memory used by the process.
TIME+ - process time.
Command - indicates the command that started the process.
Through the settings (F2) you can add some more useful parameters:
IO RATE - I / O operations. Read + write. If you need to separately read and write, then you can add:
IO READ RATE and IO WRITE RATE.
The following parameters are also displayed on the screen:
Load average - reflects the number of blocking processes in the queue for execution in a certain time interval, namely 1 minute, 5 minutes and 15 minutes, respectively. A blocking process is a process that is waiting for resources to continue running.
Uptime - system uptime.
Management:
F1 - help;
F2 - settings;
F3 - search for a process;
F4 - sorting the list of processes (largest to smallest or smallest to largest);
F5 - sets the tree view (roots are parent processes, and leaves are child processes) and vice versa;
F6 - opens a panel with a choice of process sorting options;
F7 - increase the priority of the current process;
F8 - decrease the priority of the current process;
F9 - kill the process;
F10 - exit the program.

Answer 2

Install Debian on Sysvinit.