Need help expanding VMFS volumn

[abateham]

Configuration:

Version: VI 3.0 / VC 2.0

I have 3 VI hosts. All three hosts "share" or can "see" the drive space presented by the SAN.

One of the LUNS makes up a single datastore (1.17TB). This datastore is presented to a single VM as a single partition.

Problem:

I needed to expand the size of the partition on the VM. So, on the SAN side I expanded the LUN by creating a METALUN.

Now on the VI side, I need to extend the datastore to see the added space. I know you can do this with VMKFSTOOS, but my question is this:

Since all three hosts see the datastore, do I have to run VMKFSTOOLS on all three hosts? ...or if I do it on one, will they all see it?

Any help appreciated.

[weinstein5]

Welcome to the Forums - You can not dynamically increase the size of a VMFS partion that way - the only you can increase the size of a VMFS partition is by adding extents -

If you find this or any other answer useful please consider awarding points by marking the answer correct or helpful

[hstagner]

I have to agree with the previous commenter. You can only extend VMFS volumes with extents (not best practice). If you have the storage available (or you can get some temporary storage), I would move or back up the data on your current VMFS partition and then recreate the VMFS partition to the larger size and move the data back. Keep in mind that the LUN can be no larger than 2TB.

Regards,

Harley

[malaysiavm]

remember, once you had increase the extend, you cannot remove it as the result to remove the extend will remove the entire datastore

Malaysia VMware Communities -

[dean_kirby · Accepted solution]

Hello,

I agree with all three previous posters but I just wanted to add a little information that may help someone in the future. I was trying to perform this same task this week with VI 3.5. I have a 600 GB datastore that is running my production VMs and I wanted to grow it so I expanded it on my Clariion CX3-10 to 1.2 TB. I came back to VC and did a rescan of the storage adapters of my 3 hosts and they all see the space so I than went to the properties of the data store and clicked Add Extent and got the warning about destroying data so I stopped and picked up the phone and called support. I got the following answer back from a storage engineer:

You were certainly on the right track! Sorry for the misnomer, but the message in the add extent wizard is actually referring to the data being lost on the volume you're extending to, not the volume that is being extended.

The only "gotcha" is that to be able to use the entire volume once you've added the extent, any VMs that are currently accessing the volume must be powered off, then each host needs to be rescanned after the add extent is done on a single host.

So, process:

- power off all VMs on the volume you're extending - on one host: rescan so you see the new volume size, use add extent wizard to add extent to datastore, rescan the storage and make sure VC is showing the right VMFS volume size

- on all other hosts: rescan the storage and ensure they're seeing the right volume size and than power on all VMs

We've put in a request to our developers to have that message changed so it's more informational and not so terrifying...

I did just end up creating a new LUN and I'm using storage vmotion to move everything but like I said, I just wanted to share some information. Hope it helps.

Dean

[abateham]

This describes exactly what I'm going through. The message is what is throwing me. I'm still a little confused on the VMKFSTOOS -X. I've used this is the past to increase the size of the partition, but forget the exact circumstance behind it.

Anyway, I thank all for the feedback.

Allan

[ibomo]

Hi,

That is used in the case you want to extend a partition at a VM level, first at the esx level with vmkfstools -x, then with diskpart (for example) at the VM level.

Funny (and different) thing if you want to extend the system partition on a windows system... but you can also solve this by presenting the .vmdk you want to extend to another VM, extend there, and then give back the extended LUN to the original VM. There is additional information for this process if interested.

Regards,

Ignacio Borrero

EMC VMware Presales Specialist EMEA South