This document discusses techniques for live migrating virtual machines and storage between physical servers and clusters with zero downtime. It describes how live migration works by copying memory and dirty pages between servers while the virtual machine remains online. It also covers storage migration techniques which mirror disk writes to new storage locations without interrupting the virtual machine. Finally, it discusses how these live migration capabilities along with cluster-aware updating and replication technologies can provide high availability and disaster recovery for virtualized workloads.

1. Didier Van Hoye - Technical Architect
Microsoft MVP & MEET Member
http://workinghardinit.wordpress.com
@workinghardinit

8. Live Migrate VM and Storage
to Clusters
Live Migrate VM and
Storage Between
Clusters
Live Migrate VM and Storage
to Stand-Alone Server
You can move a VM anywhere in your datacenter with zero downtime!

9. Client accessing VM
Live Migrate this
VM to another
physical machine
VHDX

10. Memory content is
copied to new server
VM pre-staged
VHDX

11. Pages are being
dirtied
Client continues
accessing VM
VHDX

12. Smaller set of
changes
Recopy of changes
VHDX

13. Partition State copied
VM Paused
VHDX

14. Old VM deleted once
migration is verified
successful
Client directed to new
host
VHDX

15. • Windows Server 2012 now supports the ability to do multiple
live migrations in parallel
• Unlimited number of live migrations can be performed in
parallel
• Default configuration of 2 simultaneous LM’s per host
• Wield this power wisely
• Excessive number of simultaneous migrations may actually result in overall
longer times than serially

16. •
•
•
•
•

18. Update
Coordinator
Admin
Initiate
Cluster-Aware Updating

20. Storage Migrate
this VHDX to
another disk
Client accessing VM
VM stays running
servicing clients
VHDX

21. New VHDX created
on new storage
VHDXVHDX

22. Writes mirrored to new
Destination VHDX
Reads are from
Source VHDX
VHDX VHDX

23. VHDX data copied from
Source to Destination
VHDXVHDX

24. Reads and Writes
transitioned to new VHDX
VHDX

26. • Protects from unplanned downtime:
• Hardware
• Host OS
• VM
• Guest OS
• Apps in VMs

27. NetFT
Node 1
ClusSvc
VMMS
User
Mode
Kernel
Mode
RHS
Guest OS
VDev
NetFT
Node 2
ClusSvc
VMMS
RHS
Guest OS
VDev
vmclusres.dllvmclusres.dll

29. FC SAS RBOD
iSCSI FCoE
SAS JBOD
Shared Storage
RAID HBA Software
Replication
Hardware
Replication
SMB
Data Replication
Application
Replication
Spaces

31. VM running on Node 2 is
unaffected
Coordination
Node
SAN Connectivity
Failure
I/O Redirected via
network
VM’s can then be live migrated to another
node with zero client downtime
VHDX

32. Cluster

33. CLUSTER CLUSTERiSCSI or FC
Guest Cluster
SAN SAN

36. VHDX VHDX

37. • Automatic and manual failover for DR
• Supports 3rd party hardware and software based replication

38. Hyper-V Replica
• RPO = 5 minutes
• RTO = Manual (longer)
• Cost = In-box in Windows Server
• Complexity = Low
Multi-Site Clustering
• RPO = 0 minutes*
• RTO = Automatic (fast)
• Cost = High
• Complexity = High
*depending on 3rd party replication solution

39. Systems in
lock step

40. Planned
Downtime
Unplanned
Downtime
Disaster Recovery