The datastore that was there but wasn't

Had an issue with a cluster where some of my vmfs datastores were present on HOST A but not B OR C. Digging into the host properties I could see the LUNs where the datastores were located from the storage controller. I noticed that the esx version where the datastores weren't present were older. So I decided to upgrade the esx host. After the upgrade even more datastores were missing. Doing some googling I found out the solution:

from the CLI do the following:

This will show you the datastores that are available.
 # esxcfg-volume -l

VMFS UUID/label: 521556dd-261dc458-6c2f-ac162d782b64/Promise VMs
Can mount: Yes
Can resignature: No (the volume is being actively used)
Extent name: eui.22bc000155ef63ec:1     range: 0 - 2096895 (MB)

VMFS UUID/label: 520e5089-cf57924a-6997-ac162d782b64/Promise SSD
Can mount: Yes
Can resignature: No (the volume is being actively used)
Extent name: eui.22a8000155c818b4:1     range: 0 - 456703 (MB)

VMFS UUID/label: 520e50ba-1a761aaa-8785-ac162d782b64/Promise SAS15K
Can mount: Yes
Can resignature: No (the volume is being actively used)
Extent name: eui.22e80001552f174d:1     range: 0 - 571135 (MB)

Mount the LUNs
# esxcfg-volume -m "Promise VMs"
Mounting volume Promise VMs

# esxcfg-volume -m "Promise SSD"
Mounting volume Promise SSD

# esxcfg-volume -m "Promise SAS15K"
Mounting volume Promise SAS15K

# esxcfg-volume -l