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Migrating a thin provisioned virtual machine

I want to move a thin provisioned Virtual machine
 Allocated Space:389G
Space Utalized:89G

in my cluster i have four Host and 9 Data Stores but none of the data store has free space equel to 389.
so my question is ca i move this VM to a host having 250 G Free.is it ok or there must be a free space equel to allocated space of thin provioned Vm which i want to move.
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kastro Abbasi
Asked:
kastro Abbasi
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1 Solution
 
Mohammed RahmanCommented:
As it is a thin lun, you should be able to move the VM to any of the host provided the data store is mapped to the host on which the VM will reside. Also, it being a thin LUN, you will not have any issues until the point the VM reaches "utilised space" of 250G (as you have 250G free)

Thin LUNs does not reserve entire allotted space on the storage system. It grows in size only when the data is written. That capacity helps optimize storage utilization because space is not allocated and then sitting idle.

You can probably shrink the allotted space on VM from 389G to less than or equal to 250G and add space to the VM at a later point of time if need be. (This is an optional step. You can move your VM to any of the 9 data stores with present settings too.) ** Again, make sure, data store is mapped to the host on which the VM will reside.
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kastro AbbasiAuthor Commented:
All the data stores are mapped as we are in a cluster and i did this many times when i have plenty of free space available on datastores.

You mean moving a Thin Provisioned vm of 389G to a Datastore of (250 G free) will cause no problem.it will take only a utalized space of 89 G.
One more thing i observerd that the block size for the Residing data store of this VM is 2MB and the destination DataStore block size is 1MB.
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
You will need to convert the VM using  VMware vCenter Converter Standalone 5.5 and crate a V2V.

This procedure, will allow you to shrink the VM, ansd adjust the OS partition and virtual machine disk, in a single procdeure. This is the only recommend VMware solution for shrinking a virtual disk.

see my EE Article, Step by Step Tutorial Instructions with Screenshots

HOW TO:  P2V, V2V for FREE - VMware vCenter Converter Standalone 5.5

HOW TO:  Synchronize changes when completing a P2V or V2V with VMware vCenter Converter Standalone 5.1

HOW TO: Improve the transfer rate of a Physical to Virtual (P2V), Virtual to Virtual Conversion (V2V) using VMware vCenter Converter Standalone 5.0
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kastro AbbasiAuthor Commented:
why should i go for this,Normally i move th VM using migrate option in vm setting from one host to another host.

still i am not clear

Can i move thin provioned vm (389)Provisoned space and 89 Utalized space to a data store (250 Free space)
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
If you want to shrink the virtual machine disk, you will need to V2V (convert).

If your other datastore has sufficient free space, then just Migrate, and that will work. (but it will not change the size of the virtual disk!)
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kastro AbbasiAuthor Commented:
This was what i want Thanx to all the effort put by u guys.
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Mohammed RahmanCommented:
@ayazabbasi:
You mean moving a Thin Provisioned vm of 389G to a Datastore of (250 G free) will cause no problem.it will take only a utalized space of 89 G.

Yes, the data store will utilize only 89G; on which the VM resides (after moved to new host)
A thin LUN is kinda virtual LUN and not entire space is hard mapped to SAN disks.

The SAN only sets the pointers that the LUN is 389G but doesn't physically reserve 389G on disks. As you keep writing data to the disks, the "utilize size" keeps growing and ACTUALLY occupying space on physical disks.

In your case, the LUN can grow from 89G upto 250G without any issues as there is free space available for LUN to grow. The problem will arise once you reach the 250G. Now, the LUN thinks it can grow upto 389G but there is no space for it to expand and will lead to issues.
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