Support running multiple media repos. (#7706)

This requires a new config option to specify which media repo should be
responsible for running background jobs to e.g. clear out expired URL
preview caches.

1 files changed, 6 insertions, 1 deletions

diff --git a/docs/workers.md b/docs/workers.md
index 7512eff43a..f4cbbc0400 100644
--- a/docs/workers.md
+++ b/docs/workers.md
@@ -307,7 +307,12 @@ expose the `media` resource. For example:
            - media
 ```
 
-Note this worker cannot be load-balanced: only one instance should be active.
+Note that if running multiple media repositories they must be on the same server
+and you must configure a single instance to run the background tasks, e.g.:
+
+```yaml
+    media_instance_running_background_jobs: "media-repository-1"
+```
 
 ### `synapse.app.client_reader`