LUN Masking

Существует такая штука, как LUN Masking.
Делаем ее мы на сторадже.
Но можем делать и на ESX(i).
Зачем ее делать?
Меня позабавил ответ на этот вопрос на одном из форумов:

once visited a customer site for a VMware/CLARiiON Health Check. The customer was unable to see a LUN that had been provisioned from the CLARiiON to the ESX Host. First I verified that a Storage Group was created on the CLARiiON and that the LUN and Host had been placed in the storage group, everything looked good on the CLARiiON. I knew it wasn't a zoning issue because the ESX host was able to see other LUNs from the CLARiiON, but I checked it anyway to be thorough. Zoning was properly configured. I then attempted to rescan the storage adapters from the vSphere client, it still did not pick up the LUN. I did a second rescan...just to be sure, and again the LUN wasn't visible to the HBA.

After about 20 minutes I thought to myself.....Nah...there is no way....nobody uses that....and so I checked to see if the LUN may have been masked from the ESX host and sure enough it was. After speaking with the onsite admin, he told me......

"Nobody here knows how to configure the CLARiiON so we have to have a consultant come in every time we need a new LUN, that consultant charges us a minimum 3-hour bill time even though it only takes him 10 minutes to do. The last time he was here I had him provision 10 LUNs and then I used this disk.mask.LUN feature to hide them so that they wouldn't be used. When we needed another LUN I figured I would go in there and "unmask" it. I totally forgot that I had done that."

В ESX(i) 4 это делается иначе, чем в версии 3 - Mask Paths.