The SAN team issued a new LUN to my hosts and I was unable to format it as I recieved the following error: “Unable to read partition information” on LUN 180 on vmhba1.

Running fdisk from the service console cleared this up, heres my output :

[root@myhost]# fdisk /vmfs/devices/disks/vmhba1\:0\:180\:0

Command (m for help): p

Disk /vmfs/devices/disks/vmhba1:0:180:0 (Sun disk label): 15 heads, 64 sectors, 24686 cylinders
Units = cylinders of 960 * 512 bytes

Device Flag Start End Blocks Id System
/vmfs/devices/disks/vmhba1:0:180:0p3 u 0 24686 11849280 5 Whole disk
/vmfs/devices/disks/vmhba1:0:180:0p4 u 0 2 960 f Unknown
/vmfs/devices/disks/vmhba1:0:180:0p5 u 2 24686 11848320 e Unknown

Command (m for help): o
Building a new DOS disklabel. Changes will remain in memory only,
until you decide to write them. After that, of course, the previous
content won’t be recoverable.

The number of cylinders for this disk is set to 24686.
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)
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

After this I was able to use the LUN as normal, really put here for my reference in the future 🙂