Eric SiebertvExpert, Author, Blogger

Blog: http://vsphere-land.com

http://searchvmware.com

Twitter: @ericsiebert

Core Technologies used for Virtual Machine Backup

About the speaker

25 year IT industry veteran.

vSphere Land blog: http://vmware-land.com/Author of popular books

vExpert nomination

Contributor to industry publications

Agenda

Virtual Environment Backup Methods

Virtual Machine Snapshots

Disk-to-Disk Backups

Volume Shadow Copy Service (VSS)

vStorage APIs

Data Deduplication

Data Compression

Virtual Environment Backup Methods

Virtualization introduces more options and flexibility Drastically different than physical infrastructures Traditional backup approach can create bottlenecks

VM disk blocks

Image Level Backups Key difference with VM backups

Image-level backups don’t need OS agents More efficient to backup VMDKs via virtualization layer Image-level backups are complete VM Image-level backups are at block level Empty disk block detection Changed disk blocks

Virtual Machine Snapshots

Writes are redirected

Changes merged into source

VM disks become read-only during a snapshot

Point-in-time picture of a VM

Deleting Virtual Machine Snapshots

Process has changed with different vSphere versions

Helper snapshot is created to hold disk writes

Snapshot 3 disk data file 10 GB

Snapshot 2 disk data file 8 GB

Snapshot 1 disk data file 5 GB

Original VM disk data file 60 GB

Helper Snapshot disk data file 1 GB

Snapshot 2 grows to 18 GB

Snapshot 1 grows to 23 GB

124 3

Deleting Virtual Machine Snapshots

In later vSphere 4.1 & later 4.0 versions, each snapshot is merged directly back into the original disk in turn

Virtual Machine Snapshot Size

>Snapshot3

Snapshot 2

Snapshot 1

Snapshot 4< +

Snapshot files grow over time in 16 MB increments Single snapshot file can never exceed size of source disk Additional changes will change the same block Multiple snapshot can exceed the size of source disk Growth rate determined by disk write activity

Virtual Machine Snapshot Usage

Snapshot

Snapshot

Snapshot

Snapshot , by themselves, are not a complete backup solution

Good for short-term recovery points

Left unchecked, snapshot can degrade performance

Snapshot enable image-based backups

Makes VM’s disks read-only for exclusive access at backup

Snapshot deleted at completion of backup process

Disk To Disk Backups

Backup Server

Primary storage Backup storage

Disk systems increasingly popular as a backup target Backup repository on disk instead of tape Most backup applications support disk targets Backup repository holds deduplicated and compressed data Target storage can be local or remote: NFS/CIFS/FTP

Disk To Disk Backups

Backup data can be replicated off-site That data can be offloaded to tape (Disk to Disk to Tape)

Backups and restores with disk are much easier and faster

Primary storage Backup storage

Backup Server

Restore

Backup

Volume Shadow Copy Service (VSS)

Mechanism for creating consistent copies Windows-based service, since Windows XP Block-level within Windows file system Manages data change and avoids file locking

VSS Components

VSS prepares file system and applications for backup VSS has several components

Initiates request to VSS serviceRequestor

Application component to work with VSSWriters

Creates the shadow copyProvider

VSS Providers Different types of providers for VSS

Volume Shadow Copy ServiceWriters Requestor

ProviderSQL, Exchange,Active Directory,

Oracle, SharePoint

Backupsoftware

Operatingsystem, storage array or system

provider

Disk Volume

VMware Consolidated Backup (VCB)

VMware File System

LAN

SAN

3rd partyBackup Vendors

VCB

VMware Consolidated Backup

VMare recognized opportunity for more efficiency VMare Consolidated Backup (VCB) introduced with VI3 VCB was a proxy server to offload backups from VM VCB mounted virtual disks to then perform image-level

backup Shifted backup overhead to VCB server from VM and host

vStorage APIs

VMware File System

LAN

SAN

3rd partyBackup Vendors

VCB

VMware Consolidated Backup vStorage API

VMware File System

LAN

SAN

3rd partyBackup Vendors

In vSphere, VCB replaced with Apls Allows 3rd party applications to deliver efficient backups vStorage APls uses to describe various ways to integrate Four categories of vStorage APls

vStorage API Categories

Array-based capabilities

Defer work to storage array

For selected I/O operations

For SAN vendors

Increase storage throughput and failover

Vendors must certify

extensions

vStorage APls for Array Integration (VAAI)

vStorage APls for Multi-pathing (VAMP)

vStorage API Categories

Integrate SRM with array replication

SRA required for storage

Successor to VCB

Address limitations of

VCB

Built into vSphere

Include VCB and new

functionality

Targeted for 3rd party

integration

vStorage APls for Site Recovery Manager (VASRM)

vStorage APls for Data Protection (VADP)

vStorage APIs for Data Protection

Two methods for using VADP to back up VMs:• Providing backup server directly access VM datastores• Using virtual appliance to hot-add VM disk file directly from datastore

Changed Block Tracking

CBT is the standout feature of VADP What blocks have changed? Best for incremental backups Allows 3rd party applications to find changes since last

backup Enables faster incremental backups and near CDP

Critical technology for baking up VMs

Full backup or replication Incremental

Changes only

Changed Block Tracking

Stores information in special –ctk.vmdk file

Fixed length file

Size varies by size of VMDK

Utilized sequence numbers that inform of changed blocks

Enabled by backup applications or advanced VM settings

Data Deduplication

Inline vs. post-processing Source vs. target Different chunking methods and hash sizes

Deduplication can increase storage efficiency

Data Deduplication

In-line is common, hash calculations are done before blocks are stored in the backup repository

Hash matches that already exist utilize references

Minimal overhead for hashing

Different hash block sizes

Smaller: Maximum dedpulication yet slower backups

Larger: Minimum deduplication yet

faster backups

Look for a VM backup program that provides deduplication

Data Compression

Compression squeezes data into the backup repository

CPU intensive Don’t skimp on resources

8 CPU cores recommended

Multiple compression

levels

Deduplication and compression dramatically reduce storage requirements

What we covered

Virtual Environment Backup Methods

Virtual Machine Snapshots

Disk-to-Disk Backups

Volume Shadow Copy Service (VSS)

vStorage APIs

Data Deduplication

Data Compression

Enjoy and share this material

Feel free to promote this material

Recommend your peers to pass certification

Blog, Tweet and share this material and your experience on Facebook

You’re an Expert? We will be happy to have you as Backup Academy contributor. Apply here.

Web: http://www.backupacademy.comE-mail: feedback@backupacademy.comTwitter: BckpAcademyFacebook: backup.academy