Why does VPS performance drop from time to time?

Question

linux

Good afternoon.
Recently raised TTFB for the site. There are no problems on the server itself: there is enough memory, disk and processor. Mysql is not heavily loaded. The problem is sporadic. Toward evening, the response of the site is within a second, during the day - about 3x. Could it be a problem with the host? Site Type - Magento . Virtualization type according to virt-what - hyperv

Answer 1

The neighbors eat the processor.

Answer 2

Neighbors are eating resources, you won’t be able to track this on your VPS, there will be no table.

Answer 3

There is such a phenomenon as a "greedy neighbor", when a client appears on the pool of virtual machines, which are VDS, which begins to make good use of the resources of some subsystem. Usually this is a disk subsystem, since other resources (CPU, RAM, Net) are initially cut according to tariff plans. With disks usually something like that. During backups or some other phenomena, performance sags are observed.
What to do? In expanded form with detailed technical parameters, write to support.
Another variant of the development of events is when they distribute resources for virtual machines to clients who are not available.

Answer 4

I thought, but it seems like at the same time in top the value of st should not be zero. I could be wrong though
top - 22:55:57 up 1 day, 7:21, 11 users, load average: 1.58, 1.22, 0.95
Tasks: 358 total, 1 running, 357 sleeping, 0 stopped, 0 zombie
Cpu(s) : 5.5%us, 0.6%sy, 1.9%ni, 91.8%id, 0.2%wa, 0.0%hi, 0.0%si, 0.0%st