fix(self-host): persist valkey and stop evicting durable state (#2240)

deploy/self-hosting/.env.example

@@ -97,3 +97,12 @@ FLUXER_DISCOVERY_ENABLED=true
 #FLUXER_POSTGRES_SHARED_BUFFERS=512MB
 #FLUXER_POSTGRES_EFFECTIVE_CACHE_SIZE=2GB
 #FLUXER_POSTGRES_WORK_MEM=8MB
+
+# The bundled Valkey holds durable state as well as cache: the bulk message
+# deletion queue, the account deletion queue and every distributed lock, none of
+# which carry an expiry. It therefore runs with an append-only file on a named
+# volume and with noeviction, so an over-limit write fails loudly instead of
+# silently deleting queued work. Only change the policy if you have moved that
+# durable state elsewhere.
+#FLUXER_VALKEY_MAXMEMORY=192mb
+#FLUXER_VALKEY_MAXMEMORY_POLICY=noeviction