Unable to delete Disk Pool from Master Server

Hello,

i am trying to delete the Disk Pool from our Master Server but its givin an error: Unable to process request because the server resource are busy.

DSM has found that an association still exsists between storage unit and the disk pool:Netbackup_StorageUnit==Netbackup_Disk_Pool(PureDisk)@Domain Name.

can u please help me out to resolve the above issue, kindly send me the steps to resolve the issue.

Thanks

Abdul Rauf