What is a persistent process?
Persistence refers to the characteristic of state that outlives the process that created it.
In other words, it's when a process your user is running continues to exist even after the process that created it is no longer running. Persistent processes can also continue to exist after the machine it is running on is powered off. In this sense, a persistent process is a process that cannot be killed or shut down.
Persistent processes at DreamHost
DreamHost does not allow persistent processes to be run on Shared servers. Persistent processes are defined as any UNIX user's command running non-interactively. Basically, something that runs while you aren't actively sitting there interacting with it through a shell window.
DreamHost reserves the right to kill any user process on a Shared server without warning or prior notification at the discretion of support or the administrators. This is done to protect other users and maintain the integrity of the shared server.
This is not just done capriciously, however. This is generally done when a process is, in any way, adversely affecting the functionality of a Shared server.
Private and Dedicated Servers
The same policies do not apply to VPS and Dedicated Servers. These types of servers can run whatever (LEGAL) processes you like. However, the owner must realize they then accept responsibility for any negative impact this may have on their machine.
What types of processes are forbidden by DreamHost?
Please refer to the Acceptable Use Policy.