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Optimize Hyper-V for SC Series
24 Dell EMC SC Series: Microsoft Hyper-V Best Practices | CML1009
2.12 Volume design considerations for SC Series
One of the design considerations for which there are often no clear answers is how many guest VMs to place
on an SC Series volume, including cluster shared volumes (CSV). In most cases, a many-to-one strategy is a
good starting point, and adjust for specific uses cases.
Some advantages for a many-to-one strategy include the following:
• Simplicity: Fewer SC Series volumes to create and administer (avoid volume sprawl).
• Ease of management: Easier to provision additional guest VMs due to not having to create new SC
Series volumes each time.
• Avoid scale boundaries: Avoid the physical and functional LUN number limits for Hyper-V clusters.
Some advantages to a one-to-one strategy include the following:
• I/O isolation: Easier to isolate and monitor disk I/O patterns for a Hyper-V guest VM.
• Quicker recovery: Ability to quickly restore a guest VM by simply replacing the original host volume
or CSV with a View Volume from an SC Series snapshot.
• Granular control over replicated data: If SC Series volumes are replicated to a second location, an
administrator has more granular control over what data gets replicated (avoid replicating unnecessary
data).
• Agility: It is often quicker to move a guest VM from one host or cluster to another by remapping the
volume rather than copying large virtual hard disk files from one volume to another over the network.
Other strategies might include placing all boot virtual hard disks on a common CSV, and data volumes on
other CSVs. Workload vendors may specify an optimal volume configuration to spread I/O over several
volumes.
2.13 Offloaded data transfer
Offloaded data transfer (ODX) reduces CPU and network utilization on a host server by offloading a file copy
process from the host server to the SC Series controllers. This feature is supported in Hyper-V environments.
SC Series controllers running SCOS 6.3.1 and newer support ODX with Windows Server 2012 and newer.
ODX is enabled by default and it is a best practice to leave it enabled, unless there is a need to obtain
performance benchmarks or troubleshoot an ODX issue.
ODX is also leveraged by Microsoft System Center Virtual Machine Manager (SCVMM) environments.
Progress bars will indicate that a copy operation is rapid copy when ODX is being leveraged to deploy a new
VM over the network from a template on the library server.
For more information, such as how to enable or disable ODX and how to establish performance benchmarks,
see the
Dell EMC SC Series and Microsoft Windows Server best practices guide.