Scaling Considerations

This section contains information that helps you estimate CPU, RAM, and disk requirements for vSLX entities.

This information is valid for both installation options:

Note

For server CPU, memory, and storage specifications, refer to vSLX server requirements.

Resource requirements

The following table lists virtual CPU (vCPU), memory, and storage requirements needed to emulate SLX-OS entities.

Table 1. Resources required for vSLX entities
Entity	CPU cores	Virtual memory (RAM)	Min. disk size	Max. disk size
SLX 9540 template	—	—	9 GB	9 GB
SLX 9540 instance	1	8 GB	1 GB	25 GB

Memory swapping

If your storage technology is solid-state drive (SSD)—rather than rotational hard-disk drive (HDD)—memory swapping into the SSD can reduce the physical "Virtual memory (RAM)" values in the preceding table. For example, a swap space of 32 GB supports four additional SLX 9540 instances.

Virtual machines (VMs)

One Virtual Machine (VM) can emulate one virtual device. vSLX uses several methodologies to optimize resource utilization among VMs:

Space efficiency: QEMU snapshot technology is used for chassis (virtual device) image creation from a template. When a chassis is created, the initial storage size is less than 200 KB. As a chassis is configured, the disk size increases.
Memory efficiency: QEMU and kernel same-page merging (KSM) support memory de-duplication among VMs, which enables sharing memory for duplicate blocks. These technologies reduce memory requirements by up to 60 percent.
CPU over-provisioning: When vSLX is used for normal control-plane traffic, CPU consumption does not exceed two vCPUs for each VM. This efficiency allows for flexibility in over-subscribing CPU resources, allowing vSLX to scale well.

SLX 9540 scaling calculations

The following equations estimate optimized server resources needed for virtual SLX 9540 devices (each SLX 9540 instance is one VM):

CPU_{SLX 9540} (number of cores) = 1 * <number-of-VMs>
MEM _{SLX 9540} (GB) = 8 * <number-of-VMs>
STORAGE_{SLX 9540} (GB) = TemplateSize _{SLX 9540} + (2 * <number-of-VMs>)

The following examples estimate the server resources needed to emulate 10 SLX 9540 instances:

CPU = 1 * 10 = 10 cores
MEM = 8 * 10 = 80 GB
STORAGE = 6 + (2 x 10) = 26 GB