Book Image

Troubleshooting vSphere Storage

By : Mike Preston
Book Image

Troubleshooting vSphere Storage

By: Mike Preston

Overview of this book

Virtualization has created a new role within IT departments everywhere; the vSphere administrator. vSphere administrators have long been managing more than just the hypervisor, they have quickly had to adapt to become a ‘jack of all trades' in organizations. More and more tier 1 workloads are being virtualized, making the infrastructure underneath them all that more important. Due to this, along with the holistic nature of vSphere, administrators are forced to have the know-how on what to do when problems occur.This practical, easy-to-understand guide will give the vSphere administrator the knowledge and skill set they need in order to identify, troubleshoot, and solve issues that relate to storage visibility, storage performance, and storage capacity in a vSphere environment.This book will first give you the fundamental background knowledge of storage and virtualization. From there, you will explore the tools and techniques that you can use to troubleshoot common storage issues in today's data centers. You will learn the steps to take when storage seems slow, or there is limited availability of storage. The book will go over the most common storage transport such as Fibre Channel, iSCSI, and NFS, and explain what to do when you can't see your storage, where to look when your storage is experiencing performance issues, and how to react when you reach capacity. You will also learn about the tools that ESXi contains to help you with this, and how to identify key issues within the many vSphere logfiles.
Table of Contents (16 chapters)
Troubleshooting vSphere Storage
Credits
About the Author
Acknowledgment
About the Reviewers
www.PacktPub.com
Preface
Index

Identifying storage contention and performance issues


One of the biggest causes of poor storage performance is quite often the result of high I/O latency values. Latency in its simplest definition is a measure of how long it takes for a single I/O request to occur from the standpoint of your virtualized applications. As we will find out later, vSphere further breaks the latency values down into more detailed and precise values based on individual components of the stack in order to aid us with troubleshooting.

But is storage latency always a bad thing? The answer to that is "it depends". Obviously, a high latency value is one of the least desirable metrics in terms of storage devices, but in terms of applications, it really depends on the type of workload we are running. Heavily utilized databases, for instance, are usually very sensitive when it comes to latency, often requiring very low latency values before exhibiting timeouts and degradation of performance.

There are however other applications...