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- Herausgeber: Packt Publishing
- Kategorie: Fachliteratur
- Sprache: Englisch
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.
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Veröffentlichungsjahr: 2013
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Table of Contents
Troubleshooting vSphere Storage
Troubleshooting vSphere Storage
Copyright © 2013 Packt Publishing
All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.
Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.
Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.
First published: November 2013
Production Reference: 1131113
Published by Packt Publishing Ltd.
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ISBN 978-1-78217-206-2
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Cover Image by Aniket Sawant (<[email protected]>)
Credits
Author
Mike Preston
Reviewers
Jason Langer
Mario Russo
Aravind Sivaraman
Eric Wright
Acquisition Editor
Owen Roberts
Commissioning Editor
Shaon Basu
Technical Editors
Kanhucharan Panda
Vivek Pillai
Project Coordinator
Aboli Ambardekar
Proofreader
Jenny Blake
Indexer
Mariammal Chettiyar
Graphics
Yuvraj Mannari
Production Coordinator
Arvindkumar Gupta
Cover Work
Arvindkumar Gupta
About the Author
Mike Preston is an IT professional and an overall tech enthusiast living in Ontario, Canada. He has held all sorts of IT titles over the last 15 years including Network Technician, Systems Administrator, Programmer Analyst, Web Developer, and Systems Engineer in all sorts of different verticals, from sales to consulting. Currently, he is working as a Systems Analyst supporting the education market near his home in Belleville, Ontario.
Mike has always had an intense passion for sharing his skills, solutions, and work with various online communities, most recently focusing on the virtualization communities. He is an avid blogger at blog.mwpreston.net and participates in many discussions on Twitter (@mwpreston). It's his passion for sharing within the virtualization community which has led to Mike receiving the vExpert award for 2012 and 2013.
Mike has presented at VMworld, VMUGs, and various virtualization conferences on numerous times both as a customer and an overall evangelist and has published different whitepapers and articles for various tech websites. His commitment to giving back to the community has resulted in his most recent venture of becoming a Toronto VMUG co-leader. He is a VMware Certified Professional in Datacenter Virtualization on both Version 4 and 5 of vSphere and is currently pursuing his VCAP5-DCA, which he hopes to accomplish by 2014.
Acknowledgment
Firstly, I would like to thank my wife Alicia for putting up with all my late night and early morning writing sessions. I would also like to thank my two children, Hayden and Clara. Without their support, the completion of this book would have been nearly impossible.
Secondly, I would like to thank my technical reviewers Jason Langer, Eric Wright, and Angelo Luciani. Having those powerful brains comb over my work is one of the best decisions I ever made.
Lastly, I would like to thank the virtualization community. Without the many hours donated by the mentors, vRockstars, and others involved in the community, I would certainly not have been able to accomplish a project of this size. It's definitely a welcoming and helpful community and I'm humbled and happy to be a part of it.
About the Reviewers
Jason Langer works as a Solutions Architect for a VMware partner in the Pacific Northwest region helping customers achieve their datacenter virtualization goals. Jason has obtained multiple levels of certification both from Microsoft and VMware and brings 15 years of IT experience to the table. When not working his day job, Jason is active in the VMware community as a member of the Seattle VMUG Steering Committee and generating content for his blog, virtuallanger.com.
He is also currently working as a technical reviewer for VMware ESXi 5.1 Cookbook, Mohammed Raffic Kajamoideen, Packt Publishing.
Mario Russo has worked as an IT Architect, a Senior Technical VMware Trainer, and in the pre-sales department. He has also worked on VMware technology since 2004.
In 2005, he worked for IBM on the First Large Project Consolidation for Telecom Italia on the Virtual VMware ESX 2.5.1 platform in Italy with Physical to Virtual (P2V) tool.
In 2007, he conducted a drafting course and training for BancoPosta, Italy, and project disaster and recovery (DR Open) for IBM and EMC.
In 2008, he worked for the Project Speed Up Consolidation BNP and the migration P2V on VI3 infrastructure at BNP Cardif Insurance.
He is a VMware Certified Instructor (VCI) and is certified in VCAP5-DCA.
He is also the owner of Business to Virtual, which specializes in virtualization solutions.
He was also the technical reviewer of the book, Implementing VMware Horizon View 5.2, Jason Ventresco, Packt Publishing.
I would like to thank my wife Lina and my daughter Gaia. They're my strength.
Aravind Sivaraman is a Virtualization Engineer with more than seven years of experience in the IT industry and for the past five years, he has been focused on virtualization solutions especially on VMware products. He has been awarded with the VMware vExpert title for the year 2013. He is a VMware Technology Network (VMTN) contributor and maintains his personal blog at http://aravindsivaraman.wordpress.com/. He can also be followed on Twitter (@ss_aravind).
I would like to thank my wife and my family members for supporting me towards the contribution of this book.
Eric Wright is a Systems Architect and VMware vExpert with a background in virtualization, business continuity, PowerShell scripting, and systems automation in many industries including financial services, health services, and engineering firms. As the author behind www.DiscoPosse.com, a technology and virtualization blog, Eric is also a regular contributor to community driven technology groups such as the VMUG organization in Toronto, Canada. You can connect with Eric at www.twitter.com/DiscoPosse.
When Eric is not working in technology, you may find him with a guitar in his hand or riding a local bike race or climbing over the obstacles on a Tough Mudder course. Eric also commits time regularly to charity bike rides and running events to help raise awareness and funding for cancer research through a number of organizations.
I wish I could thank everyone personally, but let me say thank you to my family, friends, and the very special people who've inspired me to be involved with technology. Thank you to the amazing and very accepting technology community who have helped me to be able to share my knowledge and to learn from the amazing minds that drive this incredible community.
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Preface
In 1998, a small company consisting of only five employees came out of stealth in Palo Alto, claiming to have successfully run Windows 95 on a virtual machine. This company was called VMware. Shortly thereafter, the first VMware product, a type 2 hypervisor dubbed Workstation 1.0 was released. In 2006, VMware really started to infiltrate the enterprise market with the release of ESX 3.0 and vCenter 2.0. Since then, the type 1 hypervisor ESX, now only ESXi, has been a major driver in providing business agility in bringing services to their customers.
When we think about many of the features that have been integrated into vSphere over the years, such as HA, vMotion, and Distributed Resource Scheduling; they all have shared one thing in common, storage requirements. With storage, more so shared storage becoming the core requirement behind many vSphere features, we need to ensure that when things go wrong, we have the tools and knowledge to identify issues, find root causes, and resolve problems as quickly as possible. When we look at the vSphere components, storage is most commonly the only item that is not local to the host. This means that with computer, memory, and network; the hosts provide the VMs with these local resources. Storage, for the most part, is a separate physical component and is shared amongst all of the hosts within your cluster, making it one of the most constrained resources and very difficult to troubleshoot.
Troubleshooting vSphere Storage provides a thorough overview of the concepts, steps, and information that vSphere administrators need to know in order to troubleshoot some of the most common storage related problems that spring up in a virtualized environment. This book provides you with the tools and knowledge that you need in order to discover and resolve the root cause of storage visibility, contention, performance, and capacity issues inside your vSphere environment.
What this book covers
In Chapter 1, Understanding vSphere Storage Concepts and Methodologies, we will get the base-level knowledge that we need in order to understand how storage inside a virtual environment functions. We will then learn the many ways in which vSphere identifies LUNs and datastores, key in any troubleshooting exercise involving storage.
In Chapter 2, Commonly Used Tools for Troubleshooting Storage, we will learn how to use the many different tools included within ESXi and vCenter that are referenced throughout the book. The fundamental knowledge of how to operate tools like esxtop is key to identifying the many storage related symptoms explained throughout the remaining chapters.
In Chapter 3, Troubleshooting Storage Visibility, we will delve into some of the most common steps we can take when our hosts are having issues connecting or seeing our storage. This chapter will cover the three major file transports; Fibre Channel, iSCSI, and NFS.
In Chapter 4, Troubleshooting Storage Contention, we will learn how to diagnose and troubleshoot one of the most common complaints by end users; slowness. By slowness, we mean storage performance and contention. We will look at the various symptoms of a performance problem, how to pinpoint the root causes, and finally some of the techniques and tools we can use to resolve them.
In Chapter 5, Troubleshooting Storage Capacity and Overcommitment, we will look at the risks that we take when implementing some of the biggest storage benefits that vSphere delivers. We will look how to effectively monitor our thinly-provisioned disks and arrays, how to protect and ensure that we aren't caught with rogue snapshots, and again, the various tools and techniques we can take to prevent issues from occurring.
In Appendix A, Troubleshooting Steps, we will highlight all of the various steps to take when certain issues appear, ensuring we are always taking a common approach when troubleshooting vSphere Storage.
In Appendix B, Statistics of esxtop, we will cover how to efficiently and interactively control the output from esxtop, and how to filter results, sort columns, and expand fields. We will also cover all of the most common storage statistics that are collected by esxtop, explaining what they represent, and at what threshold we should begin to investigate further.
In Appendix C, iSCSI Error Codes, we will learn how to decipher and understand the various error codes that the software iSCSI initiator will dump to our ESXi logfiles.
What you need for this book
In order to follow along with some of the troubleshooting exercises throughout this book, you will need at least one ESXi host, preferably managed by vCenter Server. Also, some of the counters, examples, and statistics mentioned throughout the book are only available if you are running vSphere 5.x or later.
Although the book is divided into chapters numbered sequentially, it is not a requirement that you follow them in order. Chapter 1, Understanding vSphere Storage Concepts and Methodologies, and Chapter 2, Commonly Used Tools for Troubleshooting Storage, will certainly give you an advantage when referencing the later chapters; however, how you chose to consume the information is completely up to you. My recommendation would be that once you have a solid understanding of the terminologies and tools listed in the first two chapters, that you chose the appropriate chapter afterwards depending on the type of issue you are troubleshooting; whether it be visibility (Chapter 3, Troubleshooting Storage Visibility), contention and performance (Chapter 4, Troubleshooting Storage Contention), or capacity and overcommitment (Chapter 5, Troubleshooting Storage Capacity and Overcommitment).
Who this book is for
This book is mainly geared towards vSphere administrators. Anyone who has responsibility for or looks after a VMware environment appreciates the fact that apart from managing the virtual infrastructure, they must have some knowledge of the components that attach to it; storage being one of the most important. This book will help the VMware administrators understand how to detect storage issues and resolve them by providing the "need to know" information about the various storage transports that ESXi utilizes.
Conventions
In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.
Code words in text are shown as follows: "In order to view a list of the PSA plugins, we use the storage core namespace of the esxcli command."
Any command-line input or output is written as follows:
New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: "Select Disk under the Resources tab."
Note
Warnings or important notes appear in a box like this.
Tip
Tips and tricks appear like this.
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Chapter 1. Understanding vSphere Storage Concepts and Methodologies
Before jumping into the details of how to troubleshoot vSphere Storage, it's best to understand the basics of how storage operates in a virtualized environment. On the whole, ESXi is a very user-friendly, easy-to-use hypervisor. However, when we look at it in terms of troubleshooting and storage, there are a lot ofcomplex scenarios and key pieces of information that we need to know in order to resolve issues as they occur.
This chapter will help us to better understand the fundamentals of how vSphere and ESXi attach to and utilize various types of storage and show us how we can identify our datastores, storage paths, and LUNs within our environment. We will also learn about the Pluggable Storage Architecture (PSA) and take a broader look at how an application running in a virtual machine accesses storage.
The topics that we'll be covering in this chapter are:
Storage virtualization
ESXi presents its storage to a VM using host-level storage virtualization techniques which essentially provide an abstraction layer between the actual physical storage, whether that is attached via a Storage Area Network (SAN), an Ethernet network or locally installed, and the virtual machines consuming the storage. This abstraction layer consists of many different components all working together to simulate that of a physical disk inside a virtual machine.
When a virtual machine is created, it will normally have at least one virtual disk assigned to it. When a virtual disk is assigned to a VM, a piece of virtual hardware called a virtual storage adapter is created in order to facilitate the communication between the VM and its underlying virtual hard disk (vmdk). The type of virtual storage adapter that is used greatly depends on the Guest Operating System
