Cant create another datastore on a LUN

[Wasisnt]

I have a 2 TB LUN and I made a 500GB datastore on it. I want to create another datastore on the same LUN but when I go to create it the LUN does not show up in the list of available storage. I think it was LUN 0 before but now LUN 0 is the local disk on the ESXi server.

[Josh26 · Accepted solution]

Hi,

Whilst there are workarounds involving fdisk, a datastore really should be "one per LUN", and the GUI doesn't make it easy to do anything else. There is nothing whatsoever to be gained by having two datastores on one LUN - just make one large one.

Remember a 2TB LUN is actually oversized, the limit is 2Tb-512b.

[Wasisnt]

So this is normal behaviour? I made the LUN slightly smaller than 2 TB for the 512b issue but thought you could make multiple datastores out of one LUN. So you are saying you should plan your LUN creations around the size you plan to use for your datastores?

[Wasisnt]

Im trying to find how to extend my datastore size on the current LUN. All I see is to add an extent. I thought it was possible to increase the datastore size to take up the rest of the free space on the LUN?

[a_p_]

I assume the LUN is on shared storage!?

In some cases growing an existing datastore is grayed out when you are connected to vCenter Server. In this case use the vSphere Client and connect to one of the hosts directly and try to grow the LUN from there. Once done, rescan the other hosts.

André

[stinklyonion]

is it really possible that you can create 2 datastore in single LUN? what i know is that you can only assign one datastore per LUN. i heard before that someone have done it, but i don't actually agree if it worked on not. if so, how did it happen?

[f10]

Yes, you can create two datastores in one LUN using the command line options but it is strongly NOT recommended due to excessive SCSI reservations, note that during the operations that require metadata changes the LUN. More SCSI reservations means more latency hence this setup is not recommended for production use.

[Wasisnt]

I guess I learned something new (again). From now on Ill make one datastore per LUN. I was able to increase my datastore size to take up the rest of the LUN by logging on to the host by itself.

Thanks for the help!