Hyper V High Availabitiy

High Availability and Disaster Recovery Considerations for Microsoft Hyper-V
Ing. Eduardo Castro, PhD
Grupo Asesor en Informática
ecastro@grupoasesor.net

Agenda
Hyper-V Virtualization Scenarios
How VM Availability, Disaster Recovery and Backup/Recovery Relate to Business Continuity
Anatomy of a Hyper-V Virtual Machine
Backup/HA/DR for Hyper-V
Backup/Recovery Implications for Hyper-V VMs
High Availability Implications for Hyper-V VMs
Disaster Recovery Implications for Hyper-V VMs
Geo-Clustered Hyper-V VM Demonstration
Summary / Q&A

Hyper-V Virtualization Scenarios
Business Continuity
Server Consolidation
Test and Dev
Dynamic Datacenter

Business Continuity
Resumption of full operations combining People, Processes and Platforms
Disaster Recovery
Site-level crisis , data and IT operations resumption
Backup and Restore
Presumes infrastructure is whole
97% is file/small unit related
High Availability
Presumes that the rest of the environment is active
Keeping the Business Running

Business Continuity w/Virtualization
Business Continuity
Virtualization reduces BC costs and minimizes business downtime by:
increasing the availability of infrastructure
extending protection to more applications
simplifying backups, recovery and DR testing
Primary Site
Secondary Site
High Availability
Disaster Recovery
Backup and Recovery
Disaster Recovery
Storage Array
Storage Array
VHD
Clustering
Shared Storage
Quick/Live Migration
Backup/Recovery
Backup/Recovery
Backup/Recovery

The Architecture of Hyper-V
VMWorkerProcesses
Parent Partition
Child Partitions
Applications
Applications
Applications
Applications
User Mode
WMIProvider
VM Service
Windows Server 2008
Non-Hypervisor Aware OS
WindowsKernel
Windows Kernel
VSP
Xen-Enabled Linux Kernel
Windows Server 2003, 2008
Kernel Mode
IHV Drivers
VMBus
Emulation
Linux VSC
VMBus
VMBus
VSC
Windows Hypervisor
Ring -1
HypercallAdapter
“Designed for Windows” Server Hardware

The Anatomy of a Hyper-V VM
.VHD – VM data
.AVHD – VM snapshots
*.BIN – Contents of VM RAM for a saved state
*.VSV – Saved state information (i.e., processor register data)
*.XML – VM configuration information in an industry-standard XML file

All VMs are assigned a unique GUID:
<logical_id type="string">056B19F3…FAD06C76416D</logical_id>
All snapshots are assigned a GUID – used to identify the snapshot and construct relative paths to .AVHDs:
<guid type="string">53E0AC2C…EE46C4F495D4</guid>
Both the virtualized NIC(s) in the VM as well as the virtual switch(es) on the host are assigned a GUID:
<ChannelInstanceGuidtype="string">{bc66…}</ChannelInstanceGuid>
<SwitchName type="string">Switch-SM-847f89…</SwitchName>
Permissions related to Hyper-VM are important to consider:
<sid type="string">S-1-5-2…</sid>

VM Backup/Recovery Challenges
Expense – Loading Agents in Each Guest OS
Protecting Virtualized Applications (Exchange, SQL, etc.)
VMs may Increase Backup/Restore Complexity
Backing up “in the guest” Versus “outside the guest” – Image or file –level recovery
Restoring to different hardware if necessary

Some VM Backup Terminology
File-Level Backup – “In the Guest”
Image-Level Backup – “On the Host”
Application Quiescing
O/S Crash Consistency
Application Crash Consistency

Types of VM Backups
Three types of Backups
Backing up the host system
May be necessary to maintain host configuration
But often, not completely necessary
The fastest fix for a broken host is often a complete rebuild
Backing up Virtual Disk Files
Fast and can be done from a single host-based backup client
Challenging to do file-level restore
Backing up VM’s from inside the VM
Slower and requires backup clients in every VM.
Resource intensive on host
Capable of doing file-level restores

Challenges of Transactional DBs
O/S Crash Consistency is fairly easy
Quiesce the NTFS file system before beginning the backup
Application Crash Consistency is much harder
Tx databases like AD, Exchange and SQL don’t quiesce just because NTFS does
Restoration without crash consistency will lose data - DB restores into “inconsistent” state and must perform a soft recovery

Dealing with Consistency
When backing up VMs, may need to consider dual approaches: file level backups and image-level backups
File-level = Restore Individual Files w/Tx Integrity
Image-level = Whole-Server Recoverability
Image-level backups may not provide application crash consistency!
MSFT and 3rd Party Solutions may integrate with VSS-aware guest OS and applications
Microsoft System Center Data Protection Manager
3rd Party Backup Solutions

Integrating Backup w/VSS
VSS = Volume Shadow Copy
No need to power down virtual machines to do backups
VSS ensures a consistent state in the virtual machine
Must have backup integration component enabled

Data Protection Manager 2007
Recovery Point Objective
15min versus RT for VSs-aware VMs
~1 day versus RT for non VSS-aware VMs
Recovery Time Objective
Automated Monitoring and Failover versus on-demand recovery
Type of Recovery Needed
Disaster Recovery – focus on getting back up and running with the latest copy ASAP
Operational Recovery & Disaster Recovery – focus on being able to recover multiple points in time

Microsoft Data Protection Manager SP1
DPM for Hyper-V
Live host-level virtual machine backup In guest consistency
Bare metal restore
Rapid recovery Continuous Data Protection
No SAN required
Protects VMs without hibernation (if OS is VSS enabled)
Secondary Site
Primary Site
Recovery
Up to every 15 minutes
WAN Connectivity

VSS/Backup Recommendations
VSS in Hyper-V does not support:
Host-level backups of pass-through VHDs.
Host-level backups of iSCSI volumes in guest VMs
Instead, use guest-based Exchange-aware streaming backup or VSS backup
VSS in Hyper-V does support host-level backups of VHDs
Hardware-based VSS backups of Exchange Storage
Supported by the vendor, not Microsoft

Hyper-V Backup Best Practices
Ensure your backup solution supports VSS
Support for the VSS writer in Hyper-V specifically
Virtual Machine Backup Best practices
Leverage the Hyper-V VSS writer to take online snapshots of virtual machines
System Center Data Protection Manager will provide Hyper-V VSS snapshots
Ability to quickly recover virtual machines
Replicate snapshots to backup location for DR

Virtualization & High Availability
Traditional Non-Virtualized Environment
Downtime is bad, but affects only one workload
Virtualized Environment
Value of the physical server goes up
Downtime is far worse because multiple workloads are affected
Virtualization and High-Availability Go Hand in Hand

Microsoft Hyper-V Quick Migration
Provides solutions for both planned and unplanned downtime
Planned downtime
Quickly move virtualized workloads to service underlying hardware
More common than unplanned
Unplanned downtime
Automatic failover to other nodes (hardware or power failure)
Not as common and more difficult
Windows Server 2008 R2 introduces Live-migration supporting movement of virtual machines between servers with no loss of service

Quick Migration Fundamentals
Save state
Save entire virtual machine state
Move virtual machine
Move storage connectivity from origin to destination host
Restore state and run
Restore virtual machine and run
VHDs
Shared Storage
Network Connectivity

Other VM Availability Scenarios
Guest-based VM clustering (using WSFC)
Cost prohibitive – requires Enterprise edition of Windows Server and shared storage
More complex to install/configure/manage
An option for cluster-aware applications
3rd party replication/failover solutions
Use software-based replication/failover to replicate VMs between Hyper-V hosts (or within VMs)
Double-Take for Hyper-V
CA XOsoft High Availability
SteelEyeLifeKeeper for Windows

Virtualization Benefits
Downtime is Expensive
More Rapid Backup and Recovery
Quick/Live Migration/Clustering
Things are Complicated
Eliminate maintaining duplicate physical systems
Automate Backup, Recovery and DR processes
Infrastructure/People are Expensive
Reduce expenditure on facility and infrastructure
Diminish need for specialized hardware/personnel

Some DR Terminology
RTO – Recovery Time Objective
How much data you can afford to lose…
RPO – Recovery Point Objective
How long you can afford to be down…
Hot site
Servers up and operational at remote site at all times.
Warm site
Servers pre-provisioned at remote site. Tasks to complete for failover to occur.
Cold site
Empty site and servers on retainer awaiting DR event.

Hyper-V Recovery "Value Meals"
$$$$

Days to Weeks Recovery
Use free or low-cost solutions to backup VMs at the host level (image-level backups)
DR site is a “cold site” with equipment available on-demand from a vendor/co-lo company
Store images to tape/disk and rotate off-site
Will need to manually restore images and fix problems ….
…and there will be problems!

Hours to Days Recovery
Use free or low-cost solutions to backup VMs at the host level (image-level backups)
DR site is a “warm site” with storage available for replicated/copies VM images
Transfer images to off-site data storage location
Some tools provide off-site capabilities
Will need to manually restore images and fix problems ….
…and there will be problems!

Minutes to Hours Recovery
Use replication to provide site-to site replication of VM data
These host-level replicated VM copies are potentially inconsistent
Can use SAN-based or host-based replication
Cost / Bandwidth trade-off
Less impact to WAN – changes being sent in real-time (compression/throttling)
Will need to attach replicated VMs to replacement equipment and fix problems

Immediate Recovery
Warm or hot site is used for DR
Storage to storage replication installed between sites
3rd party replication technologies used for VM replication
“in the guest” for transactional integrity
“on the host” for all other workloads
Restoration is usually automated using 3rd party tools or interoperability with Windows Server Failover Clustering

Windows Server 2008 - WSFC
No More Single-Subnet Limitation
Allows cluster nodes to communicate across network routers
No more having to connect nodes with VLANs!
Configurable Heartbeat Timeouts
Increase to extend geographically dispersed clusters over greater distances
Storage Vendor Based Solution
Mirrored storage between stretched locations
Hardware or Software based replication

GeoCluster
Integrates with Microsoft Failover Clustering
Uses Double-Take Patented Replication
Extends Clusters Across Geographical Distances
Eliminates Single Point of Disk Failure
GeoCluster for Hyper-V Workloads
Utilizes GeoCluster technology to extend Hyper-V clustering across virtual hosts without the use of shared disk
Allows manual and automatic moves of cluster resources between virtual hosts

At failover, the new active node resumes with current, replicated data
Only the active node accesses its disks
Data is replicated to all passive nodes
Replication
GeoCluster nodes use separate disks, kept synchronized by real-time replication
How GC Integrates w/WSFC

question & answer

© 2009 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

Hyper V High Availabitiy

by Eduardo Castro on Sep 05, 2009

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