在对一个新的LUN进行fdisk ，碰到1号主分区已经被用或者 No free sectors available 的错误，一般是原来用过这个LUN,      No free sectors available 的意思是没有磁盘分区可以使用，也就是整个磁盘已经划分并分配过了(也就是原来已经被使用过的) 。 

[root@mxrac01 etc]# fdisk  /dev/emcpowera 

The number of cylinders for this disk is set to 52339.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
   (e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): m
Command action
   a   toggle a bootable flag
   b   edit bsd disklabel
   c   toggle the dos compatibility flag
   d   delete a partition
   l   list known partition types
   m   print this menu
   n   add a new partition
   o   create a new empty DOS partition table
   p   print the partition table
   q   quit without saving changes
   s   create a new empty Sun disklabel
   t   change a partition's system id
   u   change display/entry units
   v   verify the partition table
   w   write table to disk and exit
   x   extra functionality (experts only)

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
e
Partition number (1-4): 4
No free sectors available

Command (m for help): q