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Virtual Machine Recommendations and Limits

Virtual machines (VMs) require certain CPU core resources and have and other limits for memory, networks, and storage.

Recommended Number of CPU Cores

The number of cores recommended for everRun workloads depends upon the number of vCPUs in each VM and the types of the VMs as described below:

Item Number of Physical Threads
Fixed system overhead (host and system management) 2
Each FT guest with n vCPUs n + 2 (typical)
Each HA guest with n vCPUs n + 1 (typical)
Note: A non-hyperthreaded physical CPU core can handle 1 physical thread. A hyper-threaded physical CPU core can handle 2 physical threads.

The actual number of required threads depends upon the workload. The guidelines above should cover most workloads. Since any given workload may require fewer or more threads, it’s good practice to test and characterize your specific workload.

Examples

A single 4-vCPU FT guest typically requires:

Four 5-vCPU FT guests typically require:

Virtual Machine Limits

For systems with many or large virtual machines (VMs), configure everRun with 10 Gb sync links, and for the everRun software itself, 4 vCPUs and 4096 MB. Refer to the Preferences -> Systems Resources page in the everRun Availability Console for instructions on setting the everRun system resources to the maximum.

The following table lists everRun system VM limits.

Item

Limits

Maximum VCPUs per FT VM

8

Maximum VCPUs per HA VM

16

Maximum Memory per FT VM 213.33 GB
Maximum Memory per HA VM 213.33 GB

Maximum Availability Links per VM

2
Maximum Virtual Networks per VM 20
Maximum Storage Volumes per VM

12

Guest Volume Size Tested up to 2.2 TB. There are no known limitations other than those imposed by the guest operating system.
Max. Snapshots per VM 16 (72 total per system)
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