Thin Provisioning

Efficient allocation of unified disk storage, saving 20-40% of data storage space to repurpose for other applications.

With IceWEB’s IceSTORM™ OS, thin provisioning means that when an iSCSI volume or Fibre Channel LUN (used synonymously here as a “volume” for simplicity) gets presented to a server, it appears as a fixed “disk” that the server has available, but no actual space reservation is made for that volume on the data storage array. Just like the airline industry overbooks flights knowing that not all passengers will show up at the gate, thin provisioning lets you “over allocate” your data storage arrays, effectively having more storage space available to your application servers than you actually have in the storage array.

IceWEB IceSTORM OS

IceWEB’s advanced and intuitive IceSTORM OS keeps track of thin provisioning and storage allocation for you, and ensures that you never accidentally run out of physical disk storage space for your files and applications. With some enterprise applications (in particular, databases), it’s appropriate to set up “arbitrarily large” drives to ensure that the application does not run out of space and avoid the dreaded “disk full” problems. All-in-all, thin provisioning is a very effective method to get a high utilization rate from your storage array.

Example: You want to create a 500GB G: drive for a Windows application server, but only 12GB is currently written to the G drive.

Most block volumes are typically 60 to 75 percent full, and file shares typically run at 75 to 80 percent of quota, so you can expect to save somewhere between 20 and 40 percent of your physical capacity by using thin provisioning.

Fully provisioned volume reserves 500GB within an array

Thin provisioned volume bypasses the 500GB reservation only 12GB of blocks are allocated within the array the remaining 482GBs are available to other volumes or snapshots as needed saves between 20 and 40 percent of your physical capacity to be repurposed until needed.

Cautions About Vendors’ Thin Provisioning Claims

Not all thin provisioning implementations are the same. Many systems must pre-allocate blocks, so the operation of “extending” a volume can be costly, involving thresholds and “extents.” Managing these systems is confusing, and can result in a significant performance impact. Not with the IceWEB Storage System. Blocks are only allocated as needed by writes, and the only difference with thin provisioning and full provisioning is the reservation step during volume creation. Thus, there is no performance penalty for using thin provisioning with the IceWEB Storage System.