Docker Disk Configuration

Determining the Quantity and Size of Disks on Docker Host

The Docker host dedicated for the Skylight orchestrator is expected. In order to reach the full engineering specifications, the following disk configurations of the Docker host are required for 5K, 15K, 30K or 60K profiles.

¹ Assuming 1 week of retention.
² RTD is Round trip delay
³Assuming the default directory of Docker images is /var/lib/docker (on the root partition) - using the same disk with the OS of Docker host.

Selecting a deployment profile that scales beyond 5,000 network elements requires that operators configure Skylight orchestrator Docker with data disks. This is needed to ensure sufficient disk space and I/O performance is available to the application.

Out of the box, the Skylight orchestrator Docker ships with its OS disk configured with the 5K profile. This profile starts up a single process called a mediation instance that is responsible for network element communications, as well as performance data collection. These operations are disk I/O intensive.

For Skylight orchestrator Docker version 23.04.1 or prior

• Whereas the 5K profile uses a single mediation instance, the 15K, 30K and 60K deployment profiles use a total of three (3), six (6) and twelve (12) mediation instances, respectively. Each mediation instance is assigned a work area under the data volume directory.

For Skylight orchestrator Docker version 23.12 or later

• Whereas the 5K profile uses a single mediation instance, the 15K, 30K and 60K deployment profiles use a total of two (2), three (3), and six (6) mediation instances, respectively. Each mediation instance is assigned a work area under the data volume directory.

In order to spread the load, it is recommend that each data disk is assigned to three mediation instances. This means that the 15K profile requires one (1) data disk, 30K profile requires two (2) data disks, and the 60K profile requires four (4) data disks.

Disk Configuration for the 5K Profile

As per the table above, the Skylight orchestrator application can run with a single disk (the same disk with OS of Docker host) when using the 5K profile. 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.

The default Skylight orchestrator application requires 65 GB of disk space (this includes disk space for Docker images, database, application log files, etc.) to work properly.

If configuration of 1,000 performance sessions and adding 100 network elements is needed, the Administrator must ensure the disk size of Docker host satisfies to allot for:

• 20 GiB 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 GiB 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 GiB of disk space per week.
• 9 GiB 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 GiB of disk space per week.

For example, if configuration to run 52,000 performance sessions on the system with less than 1,000 Skylight devices (the minimum allotted for Skylight devices) is needed, the free disk size necessary for Docker host:

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

  312 + 20 + 65 = 397 GB.

Disk Configuration for the 15K Profile

The 15K profile requires the addition of one 750 GB disk to the Docker host which deployed the Skylight orchestrator.

It is highly recommended to split out this new 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.

In order to spread the load, it is recommended that each data disk be assigned to three mediation instances. This means that the 15K profile requires one (1) data disk and it is assigned to:

• Three (3) mediation instances with Skylight orchestrator Docker version 23.04.1 or prior.
• Two (2) mediation instances with Skylight orchestrator Docker version 23.12 or later

For instructions on how to configure mediation volumes, refer to Assigning the Profile in Docker.

Disk Configuration for the 30K Profile

The 30K profile requires the addition of two 750 GB disks to the Docker host which deployed the Skylight orchestrator. This is done by creating two new hard disks in the hypervisor and assigning these disks to the Docker host.

It is highly recommended to split out this new 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.

In order to spread the load, it is recommended that each data disk be assigned to three mediation instances. This means that the 30K profile requires two (2) data disks and it is assigned to:

• Six (6) mediation instances with Skylight orchestrator Docker version 23.04.1 or prior.
• Three (3) mediation instances with Skylight orchestrator Docker version 23.12 or later

For instructions on how to configure mediation volumes, refer to Assigning the Profile in Docker.

Disk Configuration for the 60K Profile

The 60K profile requires the addition of four 750 GB disks to the Docker host which deployed the Skylight orchestrator. This is done by creating two new hard disks in the hypervisor and assigning these disks to the Docker host.

It is highly recommended to split out this new 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.

In order to spread the load, it is recommended that each data disk be assigned to three mediation instances. This means that the 60K profile requires four (4) data disks and it is assigned to

• Twelve (12) mediation instances with Skylight orchestrator Docker version 23.04.1 or prior.
• Six (6) mediation instances with Skylight orchestrator Docker version 23.12 or later

For instructions on how to configure mediation volumes, refer to Assigning the Profile in Docker.

For specific deployment considerations, see Docker Environment Guidelines in the Release Notes.