For backing up the Solr 4 indexes using the Share Admin Console or the SkyVault-global.properties file, or JConsole, see Backing up Solr 4.
To restore the backup successfully, the contentstore directory and database must be backed up as a single unit. When you restore a SkyVault backup, you must restore both the dir.root directory (contentstore directory) and the SkyVault database from the same backup set. Otherwise, the repository may be corrupted.
The dir.root directory is defined in the SkyVault-global.properties file. By default, this directory is named alf_data and is located within the directory where SkyVault is installed.
Cause: It occurs because the cloned node contains the cluster id from production and tries to join that cluster.
Solution: To avoid the problem you should ensure any cloned nodes required for upgrade testing are network isolated from the production nodes.