Troubleshooting Linux Storage: A systems administrator guide

Length: 230 pages
Edition: 1
Language: English
Publisher: Independently published
Publication Date: 2022-09-21
ISBN-10: B0BFX744GY
ISBN-13: 9798745038433
Sales Rank: #1209158 (See Top 100 Books)

The can of worms, Pandora’s box, hornets nest, snake in the grass, boil the ocean. Now that we have the idioms out of the way, here is the first statement: “There are hundreds of ways to troubleshoot storage related issues and this book is not a silver bullet to solve all your problems!”. This book is also not a deep-dive into the architecture or code of every kernel piece you can find in relation to storage. That would really be like boiling the ocean. It also is no guide into designing end-to-end storage infrastructures. There is a great deal of knowledge and experience required in order to get application IO behaviour in line with storage capabilities. Every piece of hardware and software from application to spindle is an important piece of the puzzle, and having even one of them wrong may have a very severe impact not only on the data-path itself but also on other shared parts of that data-path. What this book will do is provide you a methodology into troubleshooting scenario’s that manifest themselves in Linux systems on various levels. Troubleshooting a storage environment is not something you’ll be able to take on lightly. There are many areas where issues may pop up. If you do not have a good knowledge of what storing and retrieving data entails in various infrastructures, you’ll soon experience you’ve ended up in a maze. A solid understanding of these environments and protocols will not only significantly reduce the chances of design and architecture issues, but also expedite resolution time in case things go wrong.

Introduction
	How the book is written
	Thank you
	Limits
	Prerequisites
Linux Troubleshooting
	TL;DR
	Performance
	The IO stack
	Applications
	Filesystem
	Encryption
	Partitions and Volume Managers
	RAID
	Block devices
	MultiPath IO
	Schedulers
	Storage Protocols
		Channel
		Transport
	Storage
Applications
	Type
	Databases
		Oracle
		Sybase (SAP ASE)
		Microsoft SQL server
		MySQL
		Reliability and Redundancy
	Cluster systems
		Operating System clusters
Filesystems
	VFS
	Disk capacity
	Layout
	Mount options
	Selecting and creating a filesystem
		EXT4
		XFS
		BTRFS
Encryption
	Using dm-crypt, cryptsetup and LUKS
	Backup and recovery
Partitioning
	Partitions
		MBR
		GPT
		Creating partitions
		Investigating GPT partitions
	Partition corruption
	Recovering partition information
		Full example GPT restoration
Volume Managers
	LVM
	What can go wrong
	PV - Physical Volumes
	VG - Volume Groups
	LV - Logical Volumes
	Thin Volumes
		Pool threshold condition reached
		File removal
	Cache volumes
		dm-writecache
		dm-cache
		Benefits of caching
		Drawbacks of caching and caching errors
	LVM corruption scenario
		Damaged PV metadata
		Recover the PV
		Recover the VG
		Reactivate the VG
	Meta-data
	Performance problems
		Monitoring performance
RAID
	Terminology
	MD
	Consistency policy
	Failures
	Data validation
	Recovery
		Adjusting raid synchronisation
	Correcting failed raidsets
	DMRAID
Block devices
	Device naming
	Identifying device characteristics
		SCSI
	Caching
Schedulers
	Non-MQ
	MQ
	Selection
	Tuning
Protocols
	Channels
	SCSI
		Logging
		Tracing
		DIF-DIX
	NVMe
	Transport
		iSCSI
		TCP/IP
	Fibre Channel
		Flow Control
		Fabrics
		HBAs
		Port up sequence
		Switches
MPIO - MultiPath IO
	ALUA
	NVMe
	Multipath.conf overrides
	IO errors
	Path failure
	Path integrity
	Error flow chart
Vendor support
	Safeguarding system state
	Opening tickets
		Severity and Criticality
	Cross Vendor support
To you the reader
References