How to add a datastore to a LUN in vmware??

At a client site, and as you can see in Picture1 (attached), there are two 15TB LUNs (EQL Backups and EQL Backups2) - two EqualLogic SAN LUNs.

However, when I go to 'storage' (Picture2), I don't see those LUNs.  Also when I click 'add storage' they don't show up.

If I click on 'devices', they show up as 'mounted', (Picture3) in the 'datastores' view they don't show up under 'device' as being connected to anything.

How do I add a datastore to point to one of those 15TB EqualLogic LUNs?
I went to 'datastores and datastore clusters' and right clicked on the datacenter, and clicked 'add datastore'.  It asks me to pick a host, then pick a storage type (I picked disk/lun), but when it asks me to pick a disk/lun it doesn't show anything.

Any ideas?  What am I doing wrong?
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
You should only use Add Datastores, when adding *new* datastores. (e.g. unformatted virgin LUNs)
This really should be labelled Add New Datastores.

All LUNs and Datastores should appear, after a Re-scan for LUNs and VMFS Datastores.

So have you re-scan the storage adaptor.

Do you have access to the console?

or remotely via SSH ?

I assume these are available on other hosts ?

These LUNs are compatible, e.g. the correct version of VMFS for the host?

I've also noticed these are both LUN 0, they are not both LUN 0 from the same SAN ? otherwise, they will LUN clash! All LUNs are supposed to be unique.
Mystical_IceAuthor Commented:
Under 'storage' and 'devices', they show up, but under 'storage' and 'datastores' view they don't.
I think they are both the same SAN.  I'm still confirming that, but they may be two different SANs.  I don't think they are as looking at the paths, the IPs are the same (

See picture

I've looked at all hosts, and I see under storage - devices, and both show they are 'mounted', but under storage - datastores I don't see them.
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
so they do not appear on ANY host ?

if this is so, the LUN IDs should be unique, especially from the same SAN.

Something odd there, two LUNs, with the same LUN ID, on the same SAN!!!!

I don't know how that has occured?

The LUN is set for concurrent access from multiple hosts?

check and compare with other working LUNs, as they are all unique.
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Mystical_IceAuthor Commented:
No they don't.

Actually, here's what I think is happening.  
See this question:

That one guest that has two 15TB volumes (RDMs) - those have got to match up to the two EqualLogic volumes.

I think I've confirmed that too - pulled the path for the RDM and the path for the device.  see "picture" that shows the RDM, and pics 1 and 2 that show the paths
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
if they are RDMs they are not datastores!


So you don't add them as datastores....because they are not datastores, they are formatted as NTFS.......(not compatble with ESXi)

They are diectly mapped to VMs, and are formatted directly, so that's why they don' show up!

Your client needs to document exactly which LUNs map to what!

Have they named the Volumes in the OS the LUN name!

It's better if they use Dell Equallogic HiT KIts for VMware and Windows (if Windows VMs), these will ensure the LUNs are mapped correctly...

To be honest with RDMs are a bit old hat and legacy today.....

What are they using 15TBx2 LUNs for ?

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Mystical_IceAuthor Commented:
LUNs are used for VEEAM backups
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Yes, I thought as much, not a very good idea, if your SAN fails, ALL your backups are also gone.

That is one very large single point of failure!

Think about it, you are copy data from the SAN, via Veeam back to the SAN?

Is this a valid backup?

if the SAN fails ? do they have another backup to restore ?

they would be better with a cheap NAS using cheaper storage for archive..
Mystical_IceAuthor Commented:
You're assuming there is one SAN.  If you look through the pictures, you'll notice two naming conventions on the LUNs - "EQL" and "CML".  EQL is an EqualLogic SAN.  CML is a Compellent SAN.  

Important to not make assumptions when it comes to this kind of thing.
Mystical_IceAuthor Commented:
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
So Veeam backups up VMs from on SAN to another SAN ?

Very good.
Mystical_IceAuthor Commented:
Yes sir - other SAN is in a different building even.
Mystical_IceAuthor Commented:
I've requested that this question be closed as follows:

Accepted answer: 0 points for Mystical_Ice's comment #a40961560

for the following reason:

iSCSI LUNs that are connected to a VM as RDMs do not show up in the datastore viewer
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
I'm going object to this, because I don't believe, that this Answer did not assist you.
Mystical_IceAuthor Commented:
The answer unfortunately did not assist me.  I asked why I could not add it as a datastore, and you never gave an answer (or at least one that was correct).  Post 5 I figured it out, and in Post 6 you gave the answer (based on my post in #5).  If you'd posted #6 before I figured it out myself in #5, then it would be yours.

I have a lot of respect for your knowledge, and you've helped me out many times, including the question I referenced in post # 5 (for which, you'll notice, I gave you the points for your answer).

Unfortunately this time around I figured it out myself - it had nothing to do with the LUN number, etc.
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
if they are RDMs they are not datastores!
Mystical_IceAuthor Commented:
That's not what I asked.  I asked why I couldn't add them as a datastore.  Your comments pointed at everything (including the fact the LUNs were not named correctly (??)) except the issue - I could not add them as a datastore as they were already mapped as RDMs.  Only time you mentioned RDMs was after I commented.

Again - Much respect - you've helped me a lot in the past and I anticipate you will in the future, but in this case what's fair is fair.  You did not provide me the answer until I figured it out myself and posted as such.  Don't be obsessed with points.  Be obsessed with providing an answer that's correct, and the points will come naturally.
Mystical_IceAuthor Commented:
Tell you what - you are a helpful member of the community, and have helped me.  I'll give you the points, and anyone that reads through this full thread in the future can view all the responses, and regardless their problem will hopefully be resolved :)
Thanks for your help
Mystical_IceAuthor Commented:
Cliffnotes:  If a LUN is mapped directly to a VM as a RDM, then it will not be available to map to a datastore.  A LUN can be RDM or Datastore, not both.
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