Home > Storage, VMware > Storage Efficiency with EMC Thin Provisioning and VMware ESX

Storage Efficiency with EMC Thin Provisioning and VMware ESX

Thin Provisioning  is a way of increasing Storage Efficiency of available storage. It is nothing but on-demand allocation of blocks of data versus the traditional method of allocating all the blocks up front also called as “thick” provisioning. EMC introduced Thin Provisioning from FLARE 29 for their CLARiiON Systems. Host operating System also needs to be aware of thin provisioning from Storage and compliment it to achieve efficiency.

How much Storage optimization with Thin provisioning and VMware ESX did we manage to achieve ?

  • Storage Pool Size: 1.6 TB
  • Thin LUN Allocation (Subscribed capacity) : 1TB + 250GB = 1.25 TB
  • Datastore Utilization: 643GB + 210GB = 853GB
  • Actual Usage on Storage Pool (Consumed capacity) = 431 GB

Space Savings = 853GB – 431G B = 422GB ~~ 50% Savings !!

Lets get some basic terminologies that are used –

ŸStorage Pool – Raid Group and Thin Pools are called so. Thin Lun can be created only from Storage Pools.
ŸThin LUN – Logical unit of storage where physical capacity allocated may be less than the user capacity seen by the host.
ŸSubscribed Capacity –  Total amount of capacity configured for thin LUNs in the pool. This could be greater than available user capacity.
ŸOversubscribed Capacity: – Amount of user capacity configured for thin LUNs that exceeds physical capacity in the thin pool.
ŸConsumed Capacity – Space used by all thin LUNs in the pool. For a thin LUN, this is the physical space used by the LUN.
ŸUser Capacity – Total amount of physical storage capacity in the thin pool that is available for thin LUNs
This Saving is based on initial deployment of Thin Provisioning itself and I am sure more savings is to come once we start loading more VM’s.
Some Considerations would be :-
Create a Storage Pool ( and not Raid Group)  and ensure you enable Thin provision on Luns that are bound from the Storage Pool.
Configure Alerts as per your Organization standards. Monitoring Storage allocation and growth in a thin provisioned environment is very critical since additional space has to be added onto Storage Pool as and when required.
In a VMware ESX environment , when creating Virtual machines on Thin Luns please go with the default option on “Create a Disk”  option as this would create lazy zeroed VMDK files.
To achieve Double Storage savings one can select Thin Provisioning at ESX Level too but I would personally not recommend it since it would require monitoring at Storage and ESX level. Why load your ESX box when we can achieve the same at the storage level ?
Note : If we select “Support clustering features such as Fault tolerance” when creating the VM , It would create eager zeroed disks which would zero on creation and you would not observe any space savings !!
When a thin LUN is first created it would consume 2GB ( 1GB Meta data and 1GB user space) per LUN and then would grow by 1GB on writes.
Categories: Storage, VMware Tags: , ,
  1. mimshad
    April 9, 2012 at 9:59 pm

    Hello Sudarshan,

    Most of Storage Guy even myself i don’t know EMC has providing Thin Provisioning in Flare OS
    itself..Just 2 months back i get to know when i was chatting with EMC.

    Thanks a lots…

  2. April 9, 2012 at 10:01 pm


  1. February 5, 2011 at 3:38 pm

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