Let’s dig into Thin Provisioning, likely the most widely available storage savings technology.
At a high level, Thin Provisioning (T.P.) is a virtual provisioning mechanism that allows addressable storage capacity to be provisioned without consuming or reserving physical capacity. The latter is allocated on-demand, as data is being written. This dynamic capability eliminates physical capacity lost as free space within traditional, thick provisioned LUNs, volumes and virtual disks.
If you’d like a deep dive into the details of thin and thick provisioned virtual disks see these posts: Thin Provisioning Part 1: The Basics & Part 2: Going Beyond.
Clarifying the Role of Thin Provisioning
Data Deduplication, Compression, and Thin Provisioning take different paths to delivering storage efficiencies. Here’s the simple way I view these technologies:
- By removing unused reserve space, T.P. maximizes physical storage capacity
- By reducing data, Dedupe and Compression increase physical storage capacity
Leveraging multiple storage savings technologies can provide unprecedented gains in usable storage capacity, resulting in significant reduction in storage costs. Pure Storage publishes the Dedupe Ticker, a publicly available real-time display of the actual data reduction and thin provisioning savings realized by our customer base. This data spans all applications and highlights the 2X multiplier I’ve previously referred to. As you can see Dedupe & Compression combine to drive an average 6:1 data reduction.
When you add Thin Provisioning to the data reduction technologies, storage savings increase to nearly 13:1. Now I must admit, measuring the savings from Thin Provisioning is somewhat nuanced. While T.P. makes it easier to fill a drive or array to capacity it doesn’t actually increase the amount of addressable storage on the drive or array. As a result the ‘benefits’ of thin provisioning can be overstated. Allow me to demonstrate how easy it is to manipulate the ‘thin provisioning effect on savings’.
Let’s compare 8 TB of data stored on a 10 TB and a 100TB Thin Provisioned LUN. You’ll notice the former provides 20% savings where as the latter 92%.
The logical data set remained 8 TB and the deduped capacity at 4 TB, yet by simply adjusting the capacity of the T.P. LUN we see an increase in T.P. Savings. There was no impact on the volume of data that is or can be stored.
In Closing
You should absolutely use every storage saving technology available on your array. The combination of Dedupe, Compression and Thin Provisioning along with additional technologies including SCSI unmap, array clones, and the removal of patterns and zeros are critical to scaling storage in the world of fixed physical datacenter capacity. This is the new norm – embrace it!
With that said… be cautious around any emphasis on T.P. While I’m not suggesting that there’s no value to T.P., you need to watch out for the thin provisioning effect on savings as it can set false expectations.
