Virtual Machine Disk Configuration

The virtual machine ships pre-configured. It has a 5K profile and a single 150 GB disk (vmdk for VMware, QCOW2 file for KVM), referred to as the OS disk. In this default configuration, the application can handle up to 1,000 performance sessions running at one-minute intervals, or up to 100 network elements.

This is adequate for demo purposes and very small networks, but it is not large enough to sustain the full engineering specifications of the 5K, 15K, 30K nor 60K profiles. In order to reach the full engineering specifications, the following disk configurations are required.

¹ Assuming 1 week of retention.
² RTD is Round trip delay

Disk Configuration for the 5K Profile

As per the table above, the application can run with a single disk when using the 5K profile. All that is required is for the OS disk to be resized at the hypervisor level. The application will automatically expand the partition on the next reboot to make the new space available.

The OS disk can be expanded up to a maximum of 2 TB. The required size of the disk is impacted by:

• The number of Skylight devices you need to manage
• The number of performance sessions you plan to add to the system
• The frequency of your performance sessions
• The retention period of your sessions.

If you wish to configure more than 1,000 performance sessions or add more than 100 network elements, you will need to resize the disk image. The generic guidelines to follow are to grow the disk image to allot for:

• 20 GB per slice of 1,000 Skylight devices
• At least one slice must be budgeted for when going beyond 100 Skylight elements or 1,000 performance sessions.
• 6 GB per slice of 1,000 performance sessions
• Sessions are configured at one-minute intervals.
• Sessions are configured for a one-week retention period.
• This rule can be applied linearly. If you are running the 1,000 sessions at five-minute intervals, you only require 1.2 GB of disk space per week.
• 9 GB per slice of 1,000 performance sessions with Round trip delay mode enabled.
• Sessions are configured at one-minute intervals.
• Sessions are configured for a one-week retention period.
• This rule can be applied linearly. If you are running the 1,000 sessions at five-minute intervals, you only require 1.8 GB of disk space per week.

As an example, if you wish to run 52,000 performance sessions on the system with less than 1,000 Skylight devices (the minimum allotted for Skylight devices), the disk size allotted to the virtual machine should be increased by:

• 20 GB for the Skylight devices
• 312 GB for the performance sessions (assuming one week retention).

When added to the initial disk size, the resulting disk image will be of:

• 150 + 312 + 20 = 482 GB.

For instructions on how to resize disk images in VMware and KVM environments, refer to Resizing Disk Space for a KVM Virtual Machine or Resizing Disk Space for a VMware Virtual Machine.

Disk Configuration for the 15K Profile

The 15K profile requires the addition of one 750 GB disk to the virtual machine. This is done by creating one new hard disk in the hypervisor and assigning this disk to the virtual machine.

For instructions on how to add a disk in VMware and KVM environments, refer to Adding Disks to Virtual Machines.

It is highly recommended to split out this new virtual disk onto a distinct physical drive or drive array, as it will need to sustain up to 15K disk I/O operations per second, with an average block size of 6 KiB, and an average latency of 5 ms. Failure to meet these specifications will lead to application down time.

Disk Configuration for the 30K Profile

The 30K profile requires the addition of two 750 GB disks to the virtual machine. This is done by creating two new hard disks in the hypervisor and assigning these disks to the virtual machine.

For instructions on how to add a disk in VMware and KVM environments, refer to Adding Disks to Virtual Machiness.

It is highly recommended to split out these new virtual disks onto distinct physical drives or drive arrays, as each virtual disk will need to sustain up to 15K disk I/O operations per second, with an average block size of 6 KiB, and an average latency of 5 ms. Failure to meet these specifications will lead to application down time.

Disk Configuration for the 60K Profile

The 60K profile requires the addition of four 750 GB disks to the virtual machine. This is done by creating four new hard disks in the hypervisor and assigning these disks to the virtual machine.

For instructions on how to add a disk in VMware and KVM environments, refer to Adding Disks to Virtual Machines.

It is highly recommended to split out these new virtual disks onto distinct physical drives or drive arrays, as each virtual disk will need to sustain up to 15K disk I/O operations per second, with an average block size of 6 KiB and an average latency of 5 ms. Failure to meet these specifications will lead to application down time.

For specific information about assigning profiles, see Assigning the Profile.