Cannot install PostgresSQL
If many VDSs on the server installed PostgreSQL, it might have reached the limit of the number of semaphore arrays. Redhat Linux kernel's default number of semaphores is 128 arrays. Each instance of PostgresSQL VA allocates a minimum of 2 arrays.
In order to increase the limits you should modify the value of : /proc/sys/kernel/sem
The best way to do that is to use the