This issue is because of your first configuration on the data stores in this server. As we checked the server I have seen one of your hard drives has 300Gb space ( It is not configured on ESXi Hard drives normally ) And i remembered you have changed the blocks of your hard drives. The huge load on the linux servers is because of the hard drive, and cpu.
Your server has 4 cores ( or totally 8 virtual cores on the cpu ) you have set 2 vps with 4 cores and another with 1 core. It could be your mistake too. bit not sure.
About your problem, it is an issue on your data store and your configuration on the hard drives.
i say that because we are offering vps on the same server even linux and windows, but we do not have any problem with our vpses and loads. If you want you can do that change that i have said