Hello Clearing the foreign configuration will delete the array. If you import the foreign configuration it will attempt to bring the foreign drives back into the array and write the preserved cache. Thanks
Hello,I have an old PE2900 with a Perc 6/i that tomorrow morning I found with the message: Foreign configuration(s) found on adapter. Press any key to continue, or ’C’ to load the configuration utility or ’F’ to import foreign configuration(s) and continue. There are offline or missing virtual drives with preserved cache. Please check the cables and ensure that all drives are present. Press any key to enter the configuration utility. I've attached the screen shots of the VD Mgmt, PD Mgmt and Foreign view from the Configuration Utility. It seems that the global hot spare has failed and I need to choose the CLEAR option but since I'm not a RAID expert I want to be sure to not choose the wrong procedure. Moreover we found that there is a problem with the backup so it is very important to put online the server and perform a fll backup as soon as possible. Thank you for your suggestions.  
Foreign configuration: import or clear