With Enterprise Vault 8.0, you cannot select the EV_DIR_DB directive with the EV_INDEX_LOCATION= and the EV_OPEN_PARTITION= directives. In addition, you should not schedule a directory database policy backup to run at the same time as an index location backup policy or an open partition backup policy.
Before you make any change in the Enterprise Vault configuration, Symantec recommends that you back up the directory database first. Then after you change the Enterprise Vault configuration, back up the directory database again. Next, perform a full backup of the Enterprise Vault components that the configuration changes affected.