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Optimize Hyper-V for SC Series
16 Dell EMC SC Series: Microsoft Hyper-V Best Practices | CML1009
• Longer chains of differencing virtual hard disks are more likely to negatively impact read performance.
It is therefore a best practice to keep native Hyper-V based checkpoints to a minimum if they are
used.
• Administrators can leverage array-based SC Series snapshots to replicate data to other SC Series
arrays for archive or recovery of Hyper-V guest VMs and workloads to avoid the use of native Hyper-
V checkpoints.
- Use SC Series Replay Manager to leverage VSS to achieve application consistency when
protecting guest VMs. For more information on Replay Manager for Hyper-V, see section 3.1.
2.3.3 Virtual hard disks and thin provisioning with SC Series storage
Disk space utilization on SC Series storage is optimized regardless of the type of virtual hard disk used due to
the advantages of thin provisioning. For all virtual hard disk types, only the actual data written by a guest VM
or workload will consume space on SC Series arrays.
The example below illustrates a 100 GB SC Series (SAN or DAS) volume presented to a Hyper-V host that
contains two 60 GB virtual hard disks. The volume is overprovisioned in this case to demonstrate behavior,
but not as a general best practice. One virtual hard disk is fixed, and the other is dynamic. Each virtual hard
disk contains 15 GB of actual data. From the perspective of the host server, 75 GB of space is consumed and
can be described as follows:
60 GB fixed disk + 15 GB of used space on the dynamic disk = 75 GB
Note: The host server reports the entire size of a fixed virtual hard disk as consumed.
Thin provisioning with SC Series storage
Compare this to how SC Series storage reports storage utilization on the same volume:
15 GB of used space on the fixed disk + 15 GB of used space on the dynamic disk = 30 GB
Note: Dynamic and fixed virtual hard disks achieve the same space efficiency on SC Series storage due to
thin provisioning. Other factors such as the I/O performance of the workload would be primary considerations
when determining the type of virtual hard disk used.