I have checked for the space on directories, and have about 8GB of file system size allocated to it.
Also, I saw that, when I kill all the postdrop, I see that they spring up again all over with sometimes going to about 100 processes.
What could be causing this issue?
Also, this issue started all of a sudden, and this is happening on our Dev servers, what would be repercussions, if this happens on our production servers?
since these processes all belong to the Postfix server, chances are high that you’re facing a lot of incoming messages. Does “postqueue -p” report a lot of messages?
If it’s actually a full queue with lots of processing that is killing your server, you might want to put all messages “on hold” (using “postsuper -h ALL”) and then check/delete/release messages one by one (“man postsuper” should give you an idea of how to do this).
What does sound a bit strange is that you save you have 8GB - is that actual free space in the file system carrying the Postfix spool space, or just the over-all size (which says absolutely nothing…)?
what would be repercussions, if this happens on our production servers?
Same as with the dev server: Too much to do, insufficient disk space, server busy. But most of all, it depends on how this was caused. If it’s actually a message flood, then you need to take counter-actions by limiting resources for Postfix (ensuring that a “loaded” Postfix doesn’t bring down all of the system → #1: separate file systems, #2: proper postfix limits configuration). If those messages are coming from internal sources, you may as well try to fix the real cause, but when the mail server is open to external messages, there’s not much you can do when you’re flooded, but limiting the effect on the remainder of the system…