Take Backup:
         a) Goto command prompt and type followings command:
               [root@localhost~]# mysqldump -u root -p koha>/root/Desktop/backup.sql

         b) Backup on external device:
                Take backup on regular basis by copying backup.sql from desktop created by above command into external device(hard-disk,pendrive,CD/DVD etc).

        c) Restore:
               Goto command prompt and type followings command:
               [root@localhost~]# mysql -u root -p koha</root/Desktop/backup.sql

    2.  To check availability of root partition space:
          a) Keep checking the root partition's space on regular basis to ensure the space is available and is not fully consumed for proper functioning of koha .
          b) Goto command prompt and type followings command:  
                  [root@localhost~]# df -h