Unable to expand/extend partition after growing SAN-based iSCSI target

Question

Hello, all. I have odd situation regarding how to expand iSCSI-based partitions.
Here is my setup:
I use the GlobalSAN iSCSI initiator on 10.6.x server (Snow Leopard).
The iSCSI LUN is formatted with the GPT partition table.
The filesystem is Journaled HFS+
My iSCSI SAN has the ability to non-destructively grow a LUN (iSCSI target).
With this in mind, I wanted to experiment with growing a LUN/target on the SAN and then expanding the Apple partition within it using disk utility. I have been unable to do so.
Here is my procedure:
1) Eject the disk (iSCSI targets show up as external hard drives)
2) Disconnect the iSCSI target using the control panel applet (provided by GlobalSAN)
3) Grow the LUN/target on the SAN.
4) Reconnect the iSCSI initiator
5) Expand/extend the partition using Disk Utility to consume the (newly created) free space.
It works until the last step. When I reconnect to the iSCSI target after expanding it on the SAN, it shows up Disk Utility as being larger than it was (so far, so expected). When I go to expand the partition, however, it errors out saying that there is not enough space.
Investigating further, I went the command line and performed a
"diskutil resizeVolume <identifier> limits"
to determine what the limit was to the partition. The limits did NOT reflect the newly-created space.
My suspicion is that the original partition map, since it was created as 100% of the volume, does not allow room for growth despite the fact that the disk suddenly (and, to the system, unexpectedly) became larger.
Is this assumption correct? Is there any way around this? I would like to be able to expand my LUNs/targets (since the SAN can grow with the business), but this has no value if I cannot also extend the partition table to use the new space.
If anyone has any insight, I would greatly appreciate it. Thank you!

Answer 1

I have exactly the same problem that you describe above. My iSCSI LUN was near capacity and therefore i extended the iSCSI LUN from 100G to 150G. No problem so far.
Disk Utility shows the iSCSI device as 150G but i cannot extend the volume to the new size. It gives me the same error (in Dutch).
Please someone help us out !