How many vCPUs and how much memory do the different Virtual Appliances support?

	32-bit Image (x86)	64-bit Image (x86_64)	64-bit Image (ARMv8)	Comment
Number of vCPU Supported
1 vCPU				32-bit image: The image will run in interrupt mode. 64-bit image: The image can run in either interrupt mode or polling mode (See below for details)
2 vCPU				The image will run in polling mode.
3 vCPU				The image will run in polling mode and use one vCPU for interface offloading.
Recommended Memory
Min	512 MB	1 GB	1 GB	cOS Core can run with less memory if needed, but this is the recommended minimum for normal operation.
Max	4 GB	16 GB	16 GB

FAQ

What is the difference between interrupt and polling mode in Virtual Appliances?

The main difference between interrupt and polling is that in interrupt, the device notifies the CPU that it requires attention while, in polling, the CPU continuously checks the status of the devices to find whether they require attention. In brief, an interrupt is asynchronous whereas polling is synchronous. This means that when running polling mode the CPU load on the VM will always be 100%.

Is the minimum recommended 2 or 3 vCPUs for the 64-bit version?

While it is possible to run using only 1 vCPU it is recommended to use at least two as one vCPU will then be used by the Linux base system which is used for memory management, disk access and more. Using only 1 vCPU may result in packet latency as both cOS Core and the Linux base will share the same CPU.

Why does the 64-bit version require 3 vCPUs to enable poll-offloading?

See previous answer, since Poll-offloading requires a dedicated vCPU it would not be enough to allocate only two vCPUs in order to enable this feature.

What are the criterias to run interrupt mode using 1 CPU Core on a 64 bit image?

Below is a small list of the requirements in order to run interrupt mode on 64 bit.

• A Virtual system.
• Only 1 CPU core allocated (so no poll-cores enabled).
• Advanced setting->Misc->"Interface Interrupt mode" must be set to Auto (default).
• The VIRT-IO interface driver is NOT used.
  
  • Note: Interrupt mode is currently verified to work with the E1000E driver for VMware. Mixing e.g. VIRT-IO and E1000E will cause it to fall back to polling mode.

Which Virtual Appliance Image should I choose, 32-bit or 64-bit Virtual Appliance?

This depends on your need, if you need many small firewalls, using as little resources as possible you should select the 32-bit image, if you need high performance the 64-bit image with multiple vCPUs are a better choice.

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