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shatztal
Contributor
Contributor

How to create a disk in VM of multiple LUN's?

i have an enviorment of ESX 3.5 and VC2.5 , EMC San Storage.

i want to take couple lun's that are 300GB and make it to 1 Disk in the vm that is 2TB, is it possible ?

there is a way to put them all in the vm as 7 diffrent disk and then in Windows to use them a spanned disk, but i don't want to do that.

plz help Smiley Happy

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AndreTheGiant
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Immortal

What you want is called VMFS extent.

But do not use it.

If you loose a LUN you loose the entire datastore.

Andre

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

It possible at the SAN level but you will need to backup and then restore data if you want one LUN, you could also create a meta LUN which would also give you logicaly one big LUN. You could use mount points under Windows to give the effect of one big disk. Basically you would mount the other disks under directories of the first then when you store data in those directories it would be stored on the disk mounted that way you have avoided spanning.

Regards

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Steve_Tron
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Enthusiast

Andre,

You only loose the whole datastore if you loose the first extent where the metadata stored, VMware will try and keep a VM within on extent therefore if you loose an extent the datastore still stays up but some vm,s will become inaccessable ie those on the extent thats down.

Regards

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AndreTheGiant
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Immortal

you could also create a meta LUN which would also give you logically one big LUN

EMC Metalun has the same problem of extent: if you loose a single LUN (that compose the metalun) you loose everything.

Best solution (as written above) is backup, recreate a bigger LUN, add to ESX, and restore.

Andre

**if you found this or any other answer useful please consider allocating points for helpful or correct answers

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

1. why sould i loose one lun? i have backup disk in the EMC . the whole idea of SAN is that even if the one disk innhi the SAN fails it has a HOT SPARE so we don't feel anything.

2. how can i make this extend you spoke about?

thx!

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Steve_Tron
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Andre,

That's true with the meta LUN however one would hope that the raid group containing the LUNs had a hot spare assigned therefore only the loss of a third drive (assuming raid 5) within the luns making up the meta lun would result in data loss. Possible yes unlikely no

Kind Regards

Steve

Steve_Tron
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Enthusiast

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AndreTheGiant
Immortal
Immortal

2. how can i make this extend you spoke about?

Go in datastore property (the first one), and simple do "Add Extent".

You can only add an empty LUN (that is not VMFS formatted).

Andre

**if you found this or any other answer useful please consider allocating points for helpful or correct answers

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