Understanding storage performance testing & metrics

If you work in IT industry, you must have came across the question of how well your network storage or even your local storage is performing. There can be many reasons for looking into storage performance including but not limited to..

  • You are evaluating new storage solution to deploy in your organization.
  • You are trying to find the bottlenecks in your existing storage solution.
  • You are product engineer and working on performance testing of storage product.

Storage Performance Testing

Measuring storage performance of a storage can be easy but finding bottleneck in storage solution can be a cumbersome task as there can be lots of hardware/software layers in a given storage solution. Let’s take an example of NAS storage product. Below diagram shows what a typical NAS storage product architecture looks like. NAS Architecture Diagram When it comes to storage performance testing, you might be testing complete solution or any layer/component as shown in above diagram. Regardless of the component you are testing, storage performance is measured using following key metrics. Before we start digging into the details, please read the article on to better under I/O size that can impact the performance results.

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Why operating system shows less disk space than what I have?

Number of times I have been asked this question as why my Operation System shows less disk space than what I have? Few years back when the disk sizes were limited to only few hundred gigabytes, this wasn’t as big of concern as the lost disk space was few gigabytes. But nowadays with disk size all the way up to 2 TB and 3TB on horizon, the lost disk space can be few hundred Gigabytes. And to make it worst, if you are building disk array (RAID or JBOD), this loss could be even more than whole 1TB.

There are few explanations for lost disk space and are explained below: Continue reading Why operating system shows less disk space than what I have?