When you log into WHM do you see this message?
The Last Attempt to Update cPanel & WHM was Blocked
Why Was the WHM Update Blocked?
WHM upgrades can be blocked for a number of reasons:
- Lack of disk space.
- Invalid license.
- Read-only file systems.
- RPM database integrity issues.
- Plugin conflicts
- MySQL version
Any of these issues can block an upgrade. To see why the update was blocked, just click the details link in the message:
In the details, we can see that WHM was blocked
Recently, we have seen an increasing number of servers with the WHM update blocked error due to MySQL. Most systems, especially CentOS and Red Hat 5 and earlier, will have MySQL 5.0 installed by default. On Red Hat or CentOS 6, you may have MySQL 5.1 installed by default.
WHM manages MySQL versions for you. You can easily update from the control panel:
MySQL Update Caution
- You cannot downgrade (easily) to a prior version of MySQL.
- WHM/cPanel does not backup your data prior to the update.
- The update will require PHP/Apache to be rebuilt.
- You need to check that your applications can use MySQL 5.5.
These are just a few of the items to consider before doing the upgrade. While MySQL 5.1 to MySQL 5.5 may not seem like a major release, there were several key differences introduced in MySQL 5.5. MySQL has documentation on incompatible changes.
A major change is that InnoDB becomes the default storage engine in MySQL 5.5. If you create a database and do not specify a storage engine, tables will be created with InnoDB instead of MyISAM tables. This can cause recovery issues on shared hosting systems since to restore a single database, you have to restore the entire InnoDB data system.
During the update process, Apache and PHP will need to be rebuilt. I have seen the updater fail to acknowledge that the rebuild succeeds. If you have an issue, you can then try to rebuild Apache via WHM or at the command line.
Once you update MySQL, you can then go back and update WHM. The process should complete now without error.