What is the reason for slow vps?

Question

Apache HTTP Server

I'm trying to figure out why the vps I've chosen is so slow.
I am using apache benchmark. When you run the
ab -n 100 -c 10 http://server_address/ command , it timeouts once out of two, and when it doesn't, the results are something like this:

During the test, the top command on the server shows the following:

Do I understand correctly, what slows down the drive? It seems that there is enough cpu, enough memory ..
If yes, then you will have to choose another hosting, because they have the ability to add cpu or memory, but to speed up the drive - there is no such possibility ...

Answer 1

Not enough RAM. Your system even started to use SWAP, and this always leads to brakes.

Answer 2

If there is little memory, I recommend installing zram, if it works, get some memory as a free bonus.

Answer 3

probably all the same because you somehow managed to find a vps with 256 megabytes of memory
, usually on such a machine the test itself cannot start, not to mention some kind of performance