GENERAL GUIDELINES TO IMPROVE HYPER-V SPEED AND ACHIEVE HIGH SYSTEM PERFORMANCE
- Don’t use dynamically expanding VHDs or VHDXs. These are only meant for test systems and are not recommended for production systems by Microsoft.
- Don’t use Hyper-V snapshots. These are also only for test and development purposes and not recommended by Microsoft for production use.
- Use large NTFS cluster sizes, such as 64K.
- Do not use drive compression of any kind.
- Use a separate drive for the Windows paging file
- Defragment all drives regularly, including from within the virtual machine operating system
- Use fixed sized VHDs with plenty of free space for the VM operating system
- Have at least 10 to 20% free space on every disk on the host. NTFS and VSS quickly become inefficient when disk space is below that limit.
- Keep at least 1 GB free RAM on the host
- Increase the VSS storage size allocation limits for each drive to at least 10% of each drive’s size. Command: vssadmin resize shadowstorage
- Increase the Windows paging file size to at least 2.5x the RAM size. Use the same setting for minimum and maximum. Ensure the paging file is not fragmented
- Make sure your system isn’t clogged with orphaned VSS snapshots. (Command: vssadmin list shadows)
GENERAL HARDWARE RECOMMENDATIONS TO IMPROVE HYPER-V SPEED
- Use high RPM drives
- Use striped RAID for virtual hard drive storage
- Use USB 3 or eSATA for external backup drives
- Use 10 Gbit Ethernet if possible for network traffic
- Isolate backup network traffic from other traffic.
- Use separate disks for VMs with high I/O requirements
- Increase the VM’s RAM
- Increase the host’s RAM. Always keep at least 1 GB available on the host
CLUSTER SHARED VOLUME RECOMMENDATIONS TO IMPROVE HYPER-V SPEED
- Try all the steps shown above first
- If using a cluster shared volume, traffic isolation is very important.
- Use separate NICs for SAN, backup, and cluster management traffic.
- Use 10 Gbit Ethernet if available
- Separate busy VMs into separate volumes
- Add additional nodes to spread the load
- Pick a time for backup when the network traffic is low.
- Disable NetBIOS over TCP/IP
- Enable jumbo packets
- Use high quality network switches
- Keep the LANs short and connect only a few nodes to each CSV. I.e. split large setups into separate CSVs
- Don’t use several switches on a Ethernet bus because each of them adds latency
BACKUP SETTINGS TO INCREASE HYPER-V BACKUP SPEED
On most systems administrators generally want to keep the Hyper-V backup process in the background so it has little if any impact on the overall system. Since most Hyper-V hosts are active 24/7, there is hardly ever a time to shut down virtual machines for the maintenance.
However, there are time windows, usually at night, where a backup process could be given additional system resources and finish faster, at the cost of a minor system slowdown.