When you log into WHM do you see this message? We encounter this issue from time to time as part of our cPanel server management services.

The Last Attempt to Update cPanel & WHM was Blocked

 

This is a warning indicating that the WHM & cPanel auto updates have been 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:

WHM update was blocked due to an outdated MySQL version. WHM 11.40 and later requires MySQL 5.1.
WHM update was blocked due to an outdated MySQL version. WHM 11.40 and later requires MySQL 5.5.

In the details, we can see that WHM was blocked

MySQL Upgrade

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:

WHM's MySQL upgrade screen. Always check your applications can use a newer version of MySQL before updating.
WHM’s MySQL upgrade screen. Always check your applications can use a newer version of MySQL before updating.

MySQL Update Caution

There’s no easy downgrade path. So do not update MySQL unless you are 100% certain your applications are compatible. If you have to restore to a prior version, you will have to do this manually at the command line.
Before updating MySQL to resolve the WHM update blocked error, there’s a few things you should consider:

  • 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.

Rebuilding Apache/PHP

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.

 

Updating WHM

Once you update MySQL, you can then go back and update WHM.   The process should complete now without error.

 

 

 

 

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