At the bottom you have an action bar and you can use the F1 to F10 keys to perform various actions. We’ll break them all down.
F1 – Help
Here you will find all the information about the other ” F” and how to find your way around HTOP. It’s very similar to Midnight Commander where you can use arrows and mouse.
F2 – Setup
You can customize and adjust the entire panel to your liking. Whether it is about adding or removing parameters to the column or in what color it should be displayed.
You can customize the entire table
F3 – Search
You write the name of the process you are looking for and it will be highlighted in yellow, and you can use the F3 key to jump to the next process with the same name.
F4 – Filter
It has the same function as “Search”, but instead specific database by industry of highlighting an individual process, it filters out all those with the same name, so you only see those processes.
F5 – Tree
A very useful function is hidden under the F5 key, which branches all processes according to how they are tied to each other. Use F5 to return the processes to their original state.
F6 – SortBy
You can sort all processes according to how they use CPU, RAM or according to user or priority.
F7 – Nice- F8 – Nice+
After clicking on an individual process, you can use the F7 keyboard to decrease the priority by one point, or use F8 to increase the priority.
F9 – Kill
If the process is angry or takes enough resources, after selecting the process and pressing F9, you can send a signal to the process to end it. This is signal 15 – SIGTERM or 9 – SIGKILL.
And finally, use keyboard F10 to exit htop
Munin
It is good to have an overview of the long-term performance of RAM and CPU. On our servers with VPS Center, you have pre-installed Munin monitoring tool , which will help with this problem.
We have already written about him several times, but repetition is the mother of wisdom.
On the screenshot you will see RAM usage in all intervals.
RAM usage in Munin
The biggest advantage is that you can view the graphs on a daily, weekly or yearly scale. This way you will find out when the load started to increase and better identify the problem.
RAM diagnostics
In the first screenshot, we can see that the server is getting enough RAM, because we don’t see the red line anywhere, which indicates the saving of processes from the operating memory to the storage disk. We can also see that cache/buffers (blue and purple colors) take up a lot of operating memory. So the server stores processes and files in RAM so that the system runs faster when they are needed again.
Many people do not know that as soon as the server runs out of operating memory, the first thing it gets rid of is the cache and buffers, so that it frees up space for new processes. So, as soon as a bigger load comes, the server will automatically release the operating memory so that it can cover the demand. He can also temporarily resort to SWAP, because he does not have time to release everything. So when you see that the server reached for SWAP, but did not access it for the next few days, that is a good sign and you do not need to increase the RAM.
Cache and Buffers are also deleted from
RAM after every server restart. So you can restart the server and immediately see how much RAM it consumes before the cache and buffers “fill up”.
Now let’s look at the worst case.
I installed Elasticsearch on my server and
You can see the change right away. The cache + buffers kiel desegni romantikan librokovrilon por elstari in the operating memory were immediately empti a red line appear there, which shows that the operating memory cannot keep up, and in order to cover the demand, it uses SWAP. This is n ot a one-time ar numbers problem, because it can be seen that the demands are not decreasing and the RAM is encroaching on the storage space for a long time and thus slowing down the entire system.
In this case, it is good to increase the RAM min. by 1GB. You can do this directly from the customer center and it’s done within 15 minutes.
