Customizable Scaling Policy

  • Updated on Mar 30, 2026
  • Published on Feb 9, 2026
  • 4 minute(s) read
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This detailed guide explains how to use Lucidity’s customizable scaling policies with step-by-step examples. Each scenario illustrates the default behavior of the scaling policy settings to help you understand how policies will impact your virtual machine (VM) disk management under various conditions.

Accessing the Policy Management Interface

  1. Log in and Navigate:

    1. Access the Lucidity dashboard.

    2. Select the 'Manage Policy' button from the menu.

  2. Creating a New Policy:

    1. Click ‘Create Policy’.

    2. Enter details as required. For example:

      1. Policy Name:

        Example_Policy

      2. Desired Utilization (%):

        1. Target percentage of disk space that should be used

        2. Includes a variance range (typically ±5%) for flexibility

        3. Helps maintain optimal balance between used and free space

      3. Minimum Buffer Size:

        1. Defines the minimum free space that must be maintained

        2. Triggers disk expansion when free space falls below this threshold

        3. Ensures sufficient space for unexpected growth

      4. Maximum Buffer Size:

        1. Sets the maximum allowed free space

        2. Triggers disk shrinkage when free space exceeds this threshold

        3. Helps optimize costs by preventing over-provisioning

      5. Maximum Disk:

        Define the upper limit for disk expansion to prevent scaling beyond a certain size. Adding data beyond this limit might result in disk downtime.

    3. Click 'Create Policy' to activate the policy.

  3. Attaching the Policy to a VM:

    1. Click on the Actions menu icon against the Instance on the Managed VM page.

    2. Select the policy that you want to apply against the instance. Click Save to apply the policy.

    3. Active policy can be confirmed / viewed by looking at the More Details popup for every instance.

How The System Works

  • Utilization Calculations

    The system manages disk space using three key metrics:

    1. Current Utilization = Used Space / Total Space

    2. Target Range = Ideal Utilization ±5%

      1. Example: 70% ideal utilization creates a 65-75% target range

    3. Required Space = Used Space / Target Utilization

      1. Example: 500GB used with 70% target = ~ 714 GB total needed

  • System Checks

    Before scaling, the system validates:

    1. Minimum Space Check

      1. Ensures free space stays above min buffer

      2. If free space would drop below min buffer, system adds capacity (expand operation)

    2. Maximum Space Check

      1. Prevents free space from exceeding max buffer

      2. If free space would exceed max buffer, system reduces capacity (shrink operation)

  • Boundary Logic

    The system uses two key boundaries to ensure proper scaling:

    1. Min Boundary:

      1. Calculated as: Min Buffer / (1 - Max Utilization%)

      2. Ensures enough total space to maintain min buffer at highest utilization

      3. Example: For 20GB min buffer at 80% max utilization:

        1. Min Boundary = 20GB / (1 - 0.8) = 100GB

    2. Max Boundary:

      • Calculated as: Max Buffer / (1 - Min Utilization%)

      • Limits total space to prevent exceeding max buffer at lowest utilization

      • Example: For 50GB max buffer at 70% min utilization:

        • Max Boundary = 50GB / (1 - 0.7) = 166.67GB

Example Scenarios

  • Case 1: Normal Operation

    Policy Setup

    • Min Buffer: 200GB

    • Max Buffer: 500GB

    • Ideal Utilization: 60%

    System Analysis

    1. Utilization Range:

      • System calculates range as Ideal ±5%

      • Results in 55-60-65% range

    2. Space Calculations:

      • Consider that data on disk is 500 GB.

      • Based on 500GB data and utilization range, system calculates:

        • Minimum provision size: 769.2GB (at 65% utilization)

        • Ideal provision size: 833.3GB (at 60% utilization)

        • Maximum provision size: 909.1GB (at 55% utilization)

    3. Free Space Checks:

      • Minimum free space: 269.2GB (> 200GB min buffer) ✅

      • Maximum free space: 409.1GB (< 500GB max buffer) ✅

      • Both checks pass, so system can use ideal utilization

    4. Final Ranges:

      • Total Provision will range between: 769.2GB - 833.3GB - 909.1GB

      • Actual Utilization will range between: 55-60-65%

      • Free Space will range between: 269.2GB - 333.3GB - 409.1GB

  • Case 2: Min Buffer Override

    Policy Setup

    • Min Buffer: 20GB

    • Max Buffer: 50GB

    • Ideal Utilization: 75%

    System Analysis

    1. Utilization Range:

      • System calculates range as Ideal ±5%

      • Results in 70-75-80% range

    2. Space Calculations:

      • Consider that data on disk is 10 GB.

      • Based on 10GB data and utilization range, system calculates:

        • Minimum provision size: 12.5GB (at 80% utilization)

        • Ideal provision size: 13.3GB (at 75% utilization)

        • Maximum provision size: 14.3GB (at 70% utilization)

    3. Free Space Checks:

      • Minimum free space: 2.5GB (<  20GB min buffer) ❌

      • Maximum free space: 4.3GB (< 50GB max buffer) ✅

      • Min buffer check fails, forcing an override.

    4. Final Ranges:

      • Total Provision: 30GB - 35GB - 40GB

      • Actual Utilization: 25-28.6-33.3%

      • Free Space: 20GB - 25GB - 30GB

      Note

      Actual utilization is much lower than target due to min buffer requirement

  • Case 3: Max Buffer Override

    Policy Setup

    • Min Buffer: 20GB

    • Max Buffer: 200GB

    • Ideal Utilization: 75%

    System Analysis

    1. Utilization Range:

      • System calculates range as Ideal ±5%

      • Results in 70-75-80% range

    2. Space Calculations:

      • Consider that data on disk is 1000 GB.

      • Based on 1000 GB data and utilization range, system calculates:

        • Minimum provision: 1250.0GB (at 80% utilization)

        • Ideal provision: 1333.3GB (at 75% utilization)

        • Maximum provision: 1428.6GB (at 70% utilization)

    3. Free Space Checks:

      • Minimum free space: 250.0GB (> 20GB min buffer) ✅

      • Maximum free space: 428.6GB (> 200GB max buffer) ❌

      • Max buffer check fails, forcing an override

    4. Final Ranges:

      • Total Provision: 1133.3GB - 1166.7GB - 1200.0GB

      • Actual Utilization: 83.3-85.7-88.2%

      • Free Space: 133.3GB - 166.7GB - 200GB

      • Note: Actual utilization is higher than target due to max buffer limitation

  • Case 4: High Utilization with Buffer Constraints

    Policy Setup

    • Min Buffer: 50GB

    • Max Buffer: 250GB

    • Ideal Utilization: 80%

    System Analysis

    1. Utilization Range:

      • System calculates range as Ideal ±5%

      • Results in 75-80-85% range

    2. Space Calculations:

      • Consider that data on disk is 4000 GB.

      • Based on 4000 GB data and utilization range, system calculates:

        • Minimum provision: 4705.9GB (at 85% utilization)

        • Ideal provision: 5000.0GB (at 80% utilization)

        • Maximum provision: 5333.3GB (at 75% utilization)

    3. Free Space Checks:

      • Minimum free space: 705.9GB (> 50GB min buffer) ✅

      • Maximum free space: 1333.3GB (> 250GB max buffer) ❌

      • Max buffer check fails, forcing an override

    4. Final Ranges:

      • Total Provision: 4150.0GB - 4200.0GB - 4250.0GB

      • Actual Utilization: 94.1-95.2-96.4%

      • Free Space: 150GB - 200GB - 250GB

      • System overrides to ensure free space doesn't exceed the 250GB max buffer

      • This results in significantly higher utilization than originally targeted (95.2% vs 80%)

      • Despite override, min buffer requirement (50GB) is still maintained

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