Thin provisioning for greater efficiencies using FlexVol volumes

With thin provisioning, when you create volumes for different purposes in a given aggregate, you do not actually allocate any space for those volumes in advance. The space is allocated only when the application host needs it.

The unused aggregate space is available for the thinly provisioned volumes to expand or for creating new volumes. By allowing as-needed provisioning and space reclamation, thin provisioning can improve storage utilization and decrease storage costs.

A FlexVol volume can share its containing aggregate with other FlexVol volumes. Therefore, a single aggregate is the shared source of all the storage used by the FlexVol volumes it contains. Flexible volumes are no longer bound by the limitations of the disks on which they reside. A FlexVol volume is a pool of storage that can be sized based on how much data you want to store in it, rather than on the size of your disk. This flexibility enables you to maximize the performance and capacity utilization of the storage systems. Because FlexVol volumes can access all available physical storage in the system, dramatic improvements in storage utilization are possible.

Example 1. Example

A 500-GB volume is allocated with only 100 GB of actual data; the remaining 400 GB allocated has no data stored in it. This unused capacity is assigned to a business application, even though the application might not need all 500 GB until later. The allocated but unused 400 GB of excess capacity is temporarily wasted.

With thin provisioning, the storage administrator provisions 500 GB to the business application but uses only 100 GB for the data. The difference is that with thin provisioning, the unused 400 GB is still available to other applications. This approach allows the application to grow transparently, and the physical storage is fully allocated only when the application truly needs it. The rest of the storage remains in the free pool to be used as needed. Storage administrators can set thresholds, so they are alerted when more disks need to be added to the pool.

The following illustration compares thin provisioning with traditional provisioning: