The cPanel disk space issues caused by a core dump have a nasty side effect of blocking cPanel updates.

If cPanel is dumping core files, then your disk space may fill up and you will get a warning email about a version change failure.  We encounter this issue from time to time as part of our cPanel server management services.

cPanel Version Change is Blocked Email

Here is an example of the notification email:

Cpanel version change is blocked

An error was detected which prevented updatenow from completing normally.
Please review the enclosed log for further details

----------------------------------------------------------------------------------------------------

[20130311.230003]   Detected version '11.34.1.12' from version file.
[20130311.230003]   Target version set to '11.36.0.11'
[20130311.230003]   Checking license
[20130311.230015]   License file check complete
[20130311.230015]   Checking that the RPM DB is OK...
[20130311.230015]   glibc-2.5-107
[20130311.230015]   OK: RPM DB is responding to queries
[20130311.230015]   Testing if rpm_is_working RPM is installed
[20130311.230015]   package rpm_is_working is not installed
[20130311.230015]   Testing if it's possible to install a simple RPM
[20130311.230015]   Preparing...                ##################################################
[20130311.230015]   rpm_is_working              ##################################################
[20130311.230015] E Blocker found: The mailserver value in /var/cpanel/cpanel.config is invalid. Valid values are dovecot or courier. You can change the value here: Mailserver Configuration
[20130311.230015] E Blocker found: The ftpserver value in /var/cpanel/cpanel.config is invalid. Valid values are pure-ftpd or proftpd. You can change the value here: FTP Server Selection
[20130311.230015] ***** FATAL: An attempt to up/downgrade to 11.36.0.11 was blocked. Please review blockers.
[20130311.230015]   The Administrator will be notified to review this output when this script completes
[20130311.230015] E Detected events which require user notification during updatenow. Will send iContact the log

Fixing the cPanel Version Block Issue

You need to fix the cPanel disk space issue first.   Once you have cleared out the core files, you can then try to update cPanel.

If you find after removing the core files, there is still not enough disk space, then you may need to also review logs.

On most cPanel servers, I find the /usr partition to often be the problem.

So check out these directories for large files:

/usr/local/apache/logs/archive

/usr/local/cpanel/logs/archive

These are two errors were large logs build up.

Another issue could be the Apache domlogs.   If they are taking up to much space, you can move them to another partition and symlink them.   Ideally you want about 1GB free on the partition containing cPanel.

Update the cPanel Version

Once you have cleared out disk space, try to update cPanel.   If it fails, then you may need to contact cPanel or your server administrator to sort things out.