Active Member
Apr 1, 2017
cPanel Access Level
DataCenter Provider
We are currently running a small cpanel setup with 2 full WHM/cPanel servers having 280-300 accounts each and with a varying number of email accounts and storage usage.
Over the last six months, we have had a few incidents where account cron jobs were not running or where the email queue did not process during the night.
We have an additional server running 5 larger eCommerce solutions and this does not have an issue.
Are there any known issues with running this number of accounts per server or is there some kind of technical limitation in the underlying libraries/tools used by cPanel.
Also, is there some kind of recommendation for how many accounts to run per server.

Current specs for the two servers are 6 CPU cores and 16GB RAM each. One has 600GB storage and the other has 300GB. Neither CPU or RAM is fully utilized and there is plenty of free disk space on both
The one having 600GB storage is the one where we most often see the issues.
We use the internal backup tools of WHM/cPanel for daily backups as well as having a VM level backup on our virtualization stack


Get Proactive!
Apr 8, 2003
Chesapeake, VA
cPanel Access Level
DataCenter Provider
There is no hard and fast rule on accounts per server. We have clients with 1200 accounts on a server and it runs fine and we have clients with 100 accounts on a server where it struggles. It all comes down to what the server load runs in steady state, how good your security/monitoring is etc.

Mail queues do not process over night, they process all day every day. You normally should not have more than 100 emails in the queue, if you have a lot more than that tyou may have a spam problem.

As for crons running over night, you have to track that down in the logs, look at the crons, try to run them manually, etc to see where the problem might lie.
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Product Owner II
Staff member
Nov 14, 2017
It reallly depends on what your clients sites are doing, how much traffic their getting - and as @GOT noted how you're monitoring and the security of the server.

we have had a few incidents where account cron jobs were not running or where the email queue did not process during the night
Tracking down what exactly was occurring here would useful - an overloaded mail server and stuck cron jobs are symptoms of an issue but not the cause.