olegarr
Enthusiast
Enthusiast

How to extend VMFS volume?

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Hello,

I have a problem and hope somebody will help me with answer.

We are using ESX 3.0.1 and VC2.

I have VMFS volume and needed to extend its size. I extend it on my SAN. And right now if I go to Configuration -- Storage, select my VMFS and go to property I can see device with new size and Primary Partition where I have my VMFS with my old capacity.

I'd like to expend this VMFS and do not loose anything what is already there.

If I go to "Add Extent" I can see Available free space, but on the next screen I have warning "The current disk layout will be destroyed. All file system and data will be lost permanently." But it's not what I want.

My question is: Can I extend VMFS volume that already have some data that I do not want to lose? How? If it's possible will it affect my production machines who already resides on this volume?

Thank you very much,

oleg

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JonT
Enthusiast
Enthusiast

olegarr,

The warning you are seeing is actually referring to the space you are adding via extents. The data on the space being added will be lost, not the data currently in your VMFS Datastore currently. If I can I will set it up in my lab to test just to make sure I don't tell you to nuke your VMDK's.

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jjpcarroll
Enthusiast
Enthusiast

Hi,

how large is your current VMFS volume?

how many VMDK's are on the volume?

how large do you want to extend the volume to?

I ask these questions because if there are to many active vmdk files on one large LUN (10 or less active vmdk files) you could get issues with locking.

If the LUN will become very large with the extent I would suggest creating a new one rather than extending.

regards,

olegarr
Enthusiast
Enthusiast

jjpcarroll, thanks for your replay

Right now I have 50GB and want to extend it to 60GB.

Right now there are two VMDK. Both of these VMs are production machines, so I really do not want to affect them...

Is it possible??

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JonT
Enthusiast
Enthusiast

olegarr,

The warning you are seeing is actually referring to the space you are adding via extents. The data on the space being added will be lost, not the data currently in your VMFS Datastore currently. If I can I will set it up in my lab to test just to make sure I don't tell you to nuke your VMDK's.

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jjpcarroll
Enthusiast
Enthusiast

Hi I believe that is correct.

regards,

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mittim12
Immortal
Immortal

I think I remember reading somewhere that once you add the extent you can't remove it without destroying all your data. Is this true?

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jjpcarroll
Enthusiast
Enthusiast

I believe that is also correct. I read it is a one way process.

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acr
Champion
Champion

I have VMFS volume and needed to extend its size.

I'd like to expend this VMFS and do not loose

anything what is already there.

My question is: Can I extend VMFS volume that

already have some data that I do not want to lose?

To answer your question, you cannot Extend a VMFS Partition..

How ever you can create another VMFS Partition and add it as an Extent, this will so as one larger VMFS Partition, but this is not best practise..

Better to creat separate VMFS Partitions and spread your VMs over these LUNs.. This will also help reduce SCSI Locks etc, should this be an issue..

jjpcarroll
Enthusiast
Enthusiast

That is what I was trying to get at with my first reply thank you for exlpaining it a lot better! Smiley Happy

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olegarr
Enthusiast
Enthusiast

Thank you all for all your help.

I set up test VMFS and did extent. It worked, however I'll follow you advice and will create new volume for better perfomance.

Thank you very much again.

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jschlach
Enthusiast
Enthusiast

I would like to add to this, make SURE you add the same new lun to all ESX hosts which see that vmfs volume. I was stuck in a situation where I completed an extend on one host but didn't make the LUN available to another esx host, which then made the extent disappear. scary Smiley Happy

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JonT
Enthusiast
Enthusiast

Just FYI I did test this in my lab with a formatted lun being added to an existing Datastore. The LUN added gave me the warning about data being lost but the VM's I had on the original LUN were not affected.

(edited due to incorrect wording)

Message was edited by:

JonT

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dshivamu
Contributor
Contributor

Hi John

I have the same scenario, initially original Lun was 512GB, i was added

256GB out of 512 GB(i.e unchecked max size and added only 256 GB during lun

allocation to datastore), but this 256 GB lun is not showing in the VCB server,

Now when I am resizing the existing extend (in my case vmhba1:1:0) , i am

getting the same warning message

*The current disk layout will be destroyed. All file system and data

will be lost permanently."*

So could you please tell me, how we can confirm if any data present on

256 GB which was added initially. So that I can go ahead to reformat disk

layout of original 512Gb Lun, and also please double confirm whether it will

destroy all data within the datastore..??

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