If you run lun resize command on NetApp you might run into the following error:
lun resize: New size exceeds this LUN’s initial geometry
The reason behind it is that each SAN LUN has head/cylinder/sector geometry. It’s not an actual physical mapping to the underlying disks and has no meaning these days. It’s simply a SCSI protocol artifact. But it imposes limitation on maximum LUN resize. Geometry is chosen at initial LUN creation and cannot be changed. Roughly you can resize the LUN to the size, which is 10 times bigger than the size at the time of creation. For example, the 50GB LUN can be extended to the maximum of 502GB. See the table below for the maximum sizes:
Initial Size Maximum Size< 50g 502g 51-100g 1004g 101-150g 1506g 151-200g 2008g 201-251g 2510g 252-301g 3012g 302-351g 3514g 352-401g 4016g
To check the maximum size for particular LUN use the following commands:
> priv set diag
> lun gemetry lun_path
> priv set
If you run into this issue, unfortunately you will need to create a new LUN, copy all the data using robocopy for example and make a cutover. Because such features as volume level SnapMirror or ndmpcopy will recreate the LUN’s geometry together with the data.
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