3.2 Storage Management

What is it?

Being in control over the storage is crucial to have the right capacity at the right time. Therefore it is required to collect performance and capacity measurements and use them to make your short and long term plans.

You have to collect certain metrics to understand the installed capacity and how that is actually used. From an energy efficiency point of view you should collect these metrics:

  • Provisioned and utilized capacity

Most storage administrators know the amount of provisioned capacity. But the challenge is often to understand how much of that provisioned capacity is actually used? The business relevance of the stored data is not in scope here, it is just measuring what is being used. There is never a reasons to buy additional storage if the provisioned capacity has "too much air". Squeeze the air out by offering capacity to the users in smaller chunks. Do the users pay for the provisioned or used capacity? That makes a big difference!

  • I/O operations per second

Storage is often about capacity. But do keep IOPS in the picture too. If performance is not that critical, collecting the data is required to troubleshoot performance problems and to learn over time what the actual IOPS load is versus the installed hardware.

  • Power draw

How much power is drawn by each storage system? You can use that data to compare storage systems and their official specifications. And you can even make energy cost part of the chargeback calculation. Likely high-end storage (tier 1) will consume more energy than low end so add those costs to the chargeback bills!


Why should you care?

Depending on who you ask, storage capacity is available or not. The administrator who provisions the storage has provisioned all storage to all users and applications, so he/she is out of storage capacity and requests to purchase additional storage units. The user of the storage, actual users and/or applications, got assigned a block of storage and is very likely not using all of it.

In the end, big money can be saved by looking at these two views and determine the real need.


How does it relate to the other items in the model?

Which KPI’s are directly related to this KPI?

  • KPI Storage Asset Efficiency requires this KPI to improve. In combination with the capacity management process the amount and utilization of devices can improve.
  • KPI Change and Configuration Management is supported by this KPI to record and store capacity data of the devices.
  • KPI Product Lifecycle Management requires this KPI to understand the actual utilization of the devices. It is input to determine the operational value and to learn what to do when the device needs replacement.
  • KPI Capacity Management is the process that uses this KPI as its input to understand the past, the current utilization and the future utilization considering stable development.
  • KPI Service Level Management matches this KPI to the expectations that are agreed in the service levels.