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.
- 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 - 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
- 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
- View randomizes the bucket order.
Bucket Load Preference RDS Host 1 MED
HIGH
MED
4
3
1
2 LOW
LOW
6
2
- 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.
- 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 - 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
- View randomizes the bucket order.
Bucket Load Preference RDS Host 1 HIGH
MED
4
1
2 LOW
LOW
5
2
- 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