Jazsko
Contributor
Contributor

Increasing "expanding" the VMFS datastore

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Hi,

I am running Esxi 4.1 servers with vCenter. At the storageside we have an Equallogic disk array iSCSI.

On that box we have 4 LUNS, on one of the LUNS we are running out of free space, can I increase the LUN on the Equallogic side, and than increase it on the VMware side?

I know from before that this wasn't recommended, but dont know how it is now with vSphere 4. Any suggestions?

thx

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idle-jam
Immortal
Immortal

extend can be done but then it would be much better to create a new LUN and then balance out your I/O request rather than one large LUN.

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idle-jam
Immortal
Immortal

extend can be done but then it would be much better to create a new LUN and then balance out your I/O request rather than one large LUN.

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nathanw
Enthusiast
Enthusiast

Consider what the impact of using extents will be upon your environment.

yes you can grow your VMFS by adding an extent but there are some limitations as I recall.

What size is your LUN now? How much extra storage are you giving it?

Can you create a new LUN and migrate your VM's to that?

How many VM's are currently on the LUN? do you really want more VM's on that LUN?

Nathan VCP
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Jazsko
Contributor
Contributor

Thx for the answers so far. I did an experiment on a fiber channel SAN. Extent end increases of LUNs are to different things if I am right?

Here is what I did on the fiber channel. I added a LUN nr. 2 on the EVA Storage. Size 5 GB. Opened vCenter and scanned the hba, the storage appeared. I added it to an ESXi server. Now when the server could see it went back to EVA storage and increased the LUN to 7GB. I rescanned all hba's and the new size appeared. Right click on it, gave me properties of the storage, at the top left corner there was a button called Increase. I pressed it, and got the option to extend it fully to 7GB. I did that, and everything worked. Is this best practices, or is this not recommended?

Now to answer your questions natanw.

My LUN is 400GB now; I'll need approximately 400 more. I can create a new LUN, BUT this is a very sensitive production environment and i can’t take down any servers, and I don’t have storage vMotion license. The number of VMs, hmm about 10 maybe, maybe less. Its Linux machines mostly.

Now a bit about the infra-structure. I have Two Equallogic disk arrays. One is running on 15k SAS disks with Raid 50, and one is running on SATA disks. The one that is running on SATA has mostly test, and development LUNS, not much space needed there, but is still using some. That doesn’t matter as I have 2.5 TB on that SAN. Now, the fast one has only 1 TB, and I tend to use it ONLY for production servers, as it is ultra-secure with the RAID 50 configuration + 2 hot spares. I am really missing storage vMotion, but we just don’t have the money for enterprise license now. So, what is the best thing to do? Create another LUN the same size, or increase the size of the existing LUN? Or, yes there is a third option  Move this LUN to the slow disk array, create one large LUN, 800-900 GB and cold migrate the VM’s to that LUN, and delete the original production LUN?

Any ideas?

Thx

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tkutil
Enthusiast
Enthusiast

Provided you have the room on the SAN and vSphere Center, you could create a new, bigger volume and storage motion the VMs.

AndreTheGiant
Immortal
Immortal

From vSphere you can do it without particular issues.

Expand the volume on Eql side.

Rescan all the host.

Then go on the datastore and choose increase.

Andre

Andre | http://about.me/amauro | http://vinfrastructure.it/ | @Andrea_Mauro