Managing the Risk of Thin Provisioning

Document created by patrick.parish on Nov 1, 2016Last modified by patrick.parish on Nov 1, 2016
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I am often asked by customers to explain the Storage Provisioned metric in Turbonomic. So here it goes! A good place to start is explaining the relationship between the Storage Amount and Storage Provisioned metrics.

 

Storage Amount refers to the actual physical storage – measuring both storage consumed and storage capacity.

 

Storage Provisioned refers to the amount of storage that we have provisioned. This is helpful to track if you leverage thin provisioning. This risk of course, is how far beyond your true capacity are you willing to provision?

 

To help manage this risk, we keep tabs on the amount of storage that has been provisioned and will provide recommendations to help you control your levels of over-provisioning. By default, the “Storage Provisioned Capacity” is double the actual storage capacity. (This is reflected as 200% in the Storage Settings in the Policy Tab…we’ll go over that shortly.)

 

So let’s take a look at a few of the datastores in my lab. One of the datastores, iSCI02 has utilized around 80% of the available storage and this is displayed as “Storage Amount”. On the other hand, our Storage Provisioned resource is at 100%. What does this mean?

 

 

By viewing the “Resources” panel on iSCSI02, we can see usage and capacity for Storage Amount and Storage Provisioned. Storage Used, Storage Capacity, and Storage Provisioned Used are all monitored values from the hypervisor. Storage Provisioned Capacity, however, is policy-defined value. By default, this value is 200% - which translates to double the Storage capacity. So from my example, my Storage Capacity is 1.5 TB but I’ve provisioned out 5.9 TB…which is well over my Storage Provisioned capactiy of 3TB.

 

This explains why Turbonomic is recommending that we Move some VMs off of this datastore and onto one of the less utilized datastores to reduce resource congestion and risk. How nice!

 

 

Storage Provisioned capacity is customizable in line with your own unique preferences. If you want to change the “Storage Provisioned Capacity,” visit the Policy tab and navigate to Analysis and scroll down the page until you see Global Storage Settings. From there you can change the “Storage Overprovisioned Percentage” to your desired value.

 

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