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Optimize Hyper-V for SC Series
20 Dell EMC SC Series: Microsoft Hyper-V Best Practices | CML1009
Use VM Settings in Hyper-V Manager to add a virtual Fibre Channel adapter to a guest VM
2.8 Guest VMs and direct attached storage
Although SC Series arrays support in-guest iSCSI and virtual FC disks mapped to guest VMs, direct-attached
storage for guest VMs is generally not recommended as a best practice unless there is a specific use case
that requires it. Typical use cases include the following:
• Application-consistent backups with SC Series Replay Manager and VSS: When the Replay
Manager agent is installed directly on a guest VM to order to obtain consistent backups of SQL
Server or Microsoft Exchange data, the protected data must reside on in-guest iSCSI volumes (SC
Series Replay Manager offers limited support for virtual FC volumes).
• SC Series Replay Manager recovery: Recovery volumes presented to a guest VM by Replay
Manager for restore or recovery operations use in-guest iSCSI.
• High I/O demand: Situations where a workload has very high I/O requirements, and the performance
gain (even if small) over using a virtual hard disk is beneficial. Direct-attached disks bypass the host
server file system. This reduces host CPU overhead for managing guest VM I/O. For many
workloads, there will be no notable difference in performance between a direct-attached or virtual
hard disk.
• High availability: VM clustering on legacy platforms prior to support for shared virtual hard disks,
which became available with the 2012 R2 release of Hyper-V and enhanced with Hyper-V 2016.
• I/O isolation: When needing to troubleshoot I/O performance on a volume and it must be isolated
from all other servers and workloads. This can be done by copying the data to a dedicated direct-
attached disk temporarily.
• Data isolation: When there is a need to create a custom SC Series storage profile, snapshot profile,
or replication profile for a specific subset of data. This can also be accomplished by placing a virtual
hard disk on a host volume that is assigned the desired SC Series storage profile(s).
• Large capacity volumes: When a single data volume presented to a guest VM will (or may) exceed
the maximum size for a VHD (2 TB) or VHDX (64 TB).