QlikView Server Loaded Document Load Balancing & Preload to Specific Nodes not Consistent

Scenario and Environment:

QlikView 11.20

QlikView Server cluster of at least 2 nodes
Separate Publisher instance

The apps that should be preloaded are not for some time after the last distribution. The distribution type does not matter.

Server 1 - QVS, QVWS/Settings, DSC
Server 2 - QVS, DSC
Server 3 - QMS, QDS, DSC

Five applications are configured containing 10M records, which causes things to run a couple of minutes for each version of the app.

QVWS load balancing is set to Loaded Document method.

Tasks 1 & 2 are set as a schedule every 8 minutes and on success respectively and the preload is set to only Server 1 but is allowed on Server 2 too.

Tasks A & B are set as above except they run on a 30 minute interval.

The remaining task is on a schedule, every 60 minutes.

Upon distribution of the updated apps, the 'preload' settings may not be respected and apps may load on other allowed nodes instead of the intended preload node.
 

The preloading option which is stored in the .meta file, is lost by the QVS instances when the app is distributed, and is not picked up again until the next scan of the .meta file occurs, leaving a default 10 minute gap where the loaded document load balance method may then result in the app loading on a different node that has lesser utilization. 

The issue will only occur if the app is distributed, so apps that are distributed prior to user sessions starting etc. will not likely encounter the issue, but situations where apps are distributed on a continual basis throughout the day may see the issue more often.  

There is no full fix for this issue, but the DocumentTimeout setting in the QVS resource Document tab settings may be adjusted to unload unused apps more quickly by reducing the time down from the default 8 hours to a lesser value, which will unload the app and free up resources more quickly.

Another setting that may be changed is the QvMetaInterval.  This setting is in minutes and the default value is 10.  This controls how often the QVS process reads the .meta files to determine which apps should be preloaded to which nodes.  The setting needs to be added to the QVS Settings.ini directly, under the [Settings 7] area.  The file is located in ProgramData\QlikTech\QlikViewServer by default.

The optimal values of both settings may be different for each environment the issue occurs, so some trial and error will need to be used in order to determine the best values that will do the best job of meeting the needs of the environment.  One key thing to keep in mind on the QvMetaInterval setting is how many .meta files there are etc. as the more files, the larger the value will likely need to be, i.e. you would not want to likely be scanning hundreds of .meta files every 1 minute.  There will likely be a performance trade-off as well.