These examples illustrate two load balancing session placement scenarios.

Example 1: No Existing User Session

This example illustrates how session placement might occur for a farm that contains six RDS hosts when a user session does not currently exist on any of the RDS hosts.

  1. Horizon Agent reports the following load preferences for each RDS host in the farm.
    RDS Host Load Preference
    1 HIGH
    2 LOW
    3 HIGH
    4 MED
    5 BLOCK
    6 LOW
  2. View sorts the RDS hosts into three buckets according to load preference. View discards RDS host 5 because Horizon Agent reported a load preference of BLOCK.
    Bucket Load Preference RDS Host
    1

    HIGH

    HIGH

    1

    3

    2

    MED

    4

    3

    LOW

    LOW

    2

    6

  3. Because bucket 2 has only one RDS host, View combines bucket 2 and bucket 3
    Bucket Load Preference RDS Host
    1

    HIGH

    HIGH

    MED

    1

    3

    4

    2

    LOW

    LOW

    2

    6

  4. View randomizes the bucket order.
    Bucket Load Preference RDS Host
    1

    MED

    HIGH

    MED

    4

    3

    1

    2

    LOW

    LOW

    6

    2

  5. View Connection Server attempts to place a new application session on RDS host 4 first, followed by RDS host 3, and so on.
    RDS Host Session Placement Order
    4
    3
    1
    6
    2
    Note: Anti-infinity rules can prevent an application from being placed on an RDS host, regardless of the reported load preference. For more information, see Configure an Anti-Affinity Rule for an Application Pool.

Example 2: Existing User Session

This example illustrates how session placement might occur for a farm that contains six RDS hosts when a user session currently exists on one of the RDS hosts. An RDS host that contains a session in which a user has previously run an application is always reused for the same application.

  1. A user session already exists on RDS host 3. RDS host 3 has a load preference of MED. The remaining RDS in the hosts in the farm (the spare list) have the following load preferences.
    RDS Host Load Preference
    1 MED
    2 LOW
    4 HIGH
    5 LOW
    6 BLOCK
  2. View sorts the RDS hosts in the spare list into two buckets according to load preference. View discards RDS host 6 because Horizon Agent reported a load preference of BLOCK.
    Bucket Load Preference RDS Host
    1

    HIGH

    MED

    4

    1

    2

    LOW

    LOW

    2

    5

  3. View randomizes the bucket order.
    Bucket Load Preference RDS Host
    1

    HIGH

    MED

    4

    1

    2

    LOW

    LOW

    5

    2

  4. View adds the RDS host that contains the existing session to the top of the new bucket ordered list.
    RDS Host Session Placement Order
    3
    4
    1
    5
    2