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removing vv from vvset - This has been asked before, but I want to verify

T. Cooper
Frequent Advisor

removing vv from vvset - This has been asked before, but I want to verify

I am running vsphere 6 and the latest 3PAR build on a 7200.

 

I have a volume in a vvset. I want to remove it from the set without disruption to the currently mapped ESXi 6 Host.

 

Is there a way to do this? Can I remove it from the vvset and retain the LUN and mapping? Can I export it to the individual host and then remove it from the vvset? I get an warning about clustered storage and so I havent gone that far, it appears to assign it an entirely different  LUN.

 

Any help is appreciated.

7 REPLIES
Sheldon Smith
Honored Contributor

Re: removing vv from vvset - This has been asked before, but I want to verify

The vvset LUNs must be contiguous - you can only remove the last VV(s) from a vvset. There can be no "holes" in the LUN numbers of the vvset.
The LUN will be deleted when you remove it from the vvset. I take it you want the VV in question to be accessed only by the particular ESX host?

As far as I know, VMware is the only OS that does not require OS-based clustering to have servers coordinate LUN access. It is my understanding VMware does it all with SCSI primitives, quickly locking and unlocking portions of a LUN to prevent other ESX hosts from accessing that part of the LUN.

Also, ESX looks at the VV WWNs, not LUN numbers. (Which is what lets Peer Persistence work.) What all this means is you can present the VV as an individual volume to the ESX host while it is also presented as part of the vvset.

Look at the paths of the datastore. Present and rescan, and you will see more paths.
Assuming you have path management set to Round Robin, those paths will be active. If, given the previous caviats, you can remove the VV from the VVset, the "older" paths will then be flagged "dead", however the ESX host will continue to work with the active paths. Again, rescan and it will clean up the old, dead paths.

 

 

Note: While I work for HP, all of my comments (whether noted or not), are my own and are not any official representation of the company.
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Note: While I work for Hewlett Packard Enterprise, all of my comments (whether noted or not), are my own and are not any official representation of the company.
----------
If my post was useful, click on my KUDOS! thumb below!
T. Cooper
Frequent Advisor

Re: removing vv from vvset - This has been asked before, but I want to verify

I will test this with a datastore hosting a single test VM. I would like there to be a check box to maintain your LUN and host mappings when leaving a vvset.

 

I also dont know why a vvset must be contiguous.

Sheldon Smith
Honored Contributor

Re: removing vv from vvset - This has been asked before, but I want to verify

No, vvsets are designed to provide the LUN mappings as volumes are added or removed from the vvset. And they were designed with the LUN numbers being continuous. That's just the way it is.
A vvset is useful for grouping LUNs that are related to a single application. For example, QoS is controlled by putting (application-)related VVs in a vvset. That does not mean, however,  the VVs in the vvset need to be exported through the vvset. 

A datastore is a repository for potentially lots of different VMs, therefore lots of different applications.


Don't have your datastore(s) in a vvset.


Note: While I work for Hewlett Packard Enterprise, all of my comments (whether noted or not), are my own and are not any official representation of the company.
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If my post was useful, click on my KUDOS! thumb below!
Dennis Handly
Acclaimed Contributor

Re: removing VV from vvset

>I have a volume in a vvset. I want to remove it from the set without disruption to the currently mapped ESXi 6 Host.

 

Why?  What are you really trying to do?

Just clone that VVset then remove that VV from the clone.  Then rename the two sets if needed.

 

>Can I remove it from the vvset and retain the LUN and mapping?

 

Not if you created the VLUN by using the VVset name.

 

>Can I export it to the individual host and then remove it from the vvset?

 

I was thinking of that too.

 

>it appears to assign it an entirely different  LUN.

 

Right, if you try to reuse the LUN, you get:

Error LUN ### is already taken.

 

>The vvset LUNs must be contiguous - you can only remove the last VV(s) from a vvset. There can be no "holes" in the LUN numbers of the vvset.

 

This isn't a 3PAR restriction.  Is it something on ESXi?

If I delete one and then add another, that LUN from the middle is reused.

I suppose this will work across a reboot since that new VV is put into the set in the old location.

 

Not sure how it handles that missing one?  Ah, that's why there are "--" entries in an exported VVset!

 

>I also don't know why a vvset must be contiguous.

 

I assume because the VLUN template only has the name, first LUN and host.

If it allowed any order, it would have to keep a list of LUNs, matching each VV in the vvset.

Sheldon Smith
Honored Contributor

Re: removing VV from vvset

Hmm. You're running ESXi 6.

If you have HP 3PAR 3.2.1 (or later), consider using VMware VVols instead of big datastore files.


Note: While I work for Hewlett Packard Enterprise, all of my comments (whether noted or not), are my own and are not any official representation of the company.
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If my post was useful, click on my KUDOS! thumb below!
T. Cooper
Frequent Advisor

Re: removing VV from vvset

I am looking at VVols. It looks like my HBA needs drivers or something.

 

update - Installed latest patches and enabled it on the 3PAR.

indylmc
Occasional Visitor

Re: removing VV from vvset