diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index d51265bde4c..1798ba5e53b 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -139,7 +139,7 @@ class ApplicationController < ActionController::Base
   end
 
   rescue_from PG::ReadOnlySqlTransaction do |e|
-    Discourse.received_readonly!
+    Discourse.received_postgres_readonly!
     Rails.logger.error("#{e.class} #{e.message}: #{e.backtrace.join("\n")}")
     raise Discourse::ReadOnly
   end
diff --git a/lib/discourse.rb b/lib/discourse.rb
index 2b53a91eb37..f1adb928c27 100644
--- a/lib/discourse.rb
+++ b/lib/discourse.rb
@@ -377,21 +377,34 @@ module Discourse
     $redis.get(PG_READONLY_MODE_KEY).present?
   end
 
-  def self.last_read_only
-    @last_read_only ||= DistributedCache.new('last_read_only', namespace: false)
+  # Shared between processes
+  def self.postgres_last_read_only
+    @postgres_last_read_only ||= DistributedCache.new('postgres_last_read_only', namespace: false)
+  end
+
+  # Per-process
+  def self.redis_last_read_only
+    @redis_last_read_only ||= {}
   end
 
   def self.recently_readonly?
-    read_only = last_read_only[$redis.namespace]
-    read_only.present? && read_only > 15.seconds.ago
+    postgres_read_only = postgres_last_read_only[$redis.namespace]
+    redis_read_only = redis_last_read_only[$redis.namespace]
+
+    (redis_read_only.present? && redis_read_only > 15.seconds.ago) ||
+      (postgres_read_only.present? && postgres_read_only > 15.seconds.ago)
   end
 
-  def self.received_readonly!
-    last_read_only[$redis.namespace] = Time.zone.now
+  def self.received_postgres_readonly!
+    postgres_last_read_only[$redis.namespace] = Time.zone.now
+  end
+
+  def self.received_redis_readonly!
+    redis_last_read_only[$redis.namespace] = Time.zone.now
   end
 
   def self.clear_readonly!
-    last_read_only[$redis.namespace] = nil
+    postgres_last_read_only[$redis.namespace] = redis_last_read_only[$redis.namespace] = nil
     Site.clear_anon_cache!
     true
   end
@@ -667,7 +680,11 @@ module Discourse
 
     if !$redis.without_namespace.get(redis_key)
       Rails.logger.warn(warning)
-      $redis.without_namespace.setex(redis_key, 3600, "x")
+      begin
+        $redis.without_namespace.setex(redis_key, 3600, "x")
+      rescue Redis::CommandError => e
+        raise unless e.message =~ /READONLY/
+      end
     end
     warning
   end
diff --git a/lib/discourse_redis.rb b/lib/discourse_redis.rb
index 85aa7077b51..d62113d7519 100644
--- a/lib/discourse_redis.rb
+++ b/lib/discourse_redis.rb
@@ -176,7 +176,7 @@ class DiscourseRedis
       end
 
       fallback_handler.verify_master if !fallback_handler.master
-      Discourse.received_readonly!
+      Discourse.received_redis_readonly!
       nil
     else
       raise ex
diff --git a/spec/components/discourse_spec.rb b/spec/components/discourse_spec.rb
index 391691ff9bf..9b3dc50b4ca 100644
--- a/spec/components/discourse_spec.rb
+++ b/spec/components/discourse_spec.rb
@@ -219,8 +219,13 @@ describe Discourse do
         expect(Discourse.readonly_mode?).to eq(true)
       end
 
-      it "returns true when Discourse is recently read only" do
-        Discourse.received_readonly!
+      it "returns true when postgres is recently read only" do
+        Discourse.received_postgres_readonly!
+        expect(Discourse.readonly_mode?).to eq(true)
+      end
+
+      it "returns true when redis is recently read only" do
+        Discourse.received_redis_readonly!
         expect(Discourse.readonly_mode?).to eq(true)
       end
 
@@ -234,21 +239,28 @@ describe Discourse do
       end
     end
 
-    describe ".received_readonly!" do
+    describe ".received_postgres_readonly!" do
       it "sets the right time" do
-        time = Discourse.received_readonly!
-        expect(Discourse.last_read_only['default']).to eq(time)
+        time = Discourse.received_postgres_readonly!
+        expect(Discourse.postgres_last_read_only['default']).to eq(time)
+      end
+    end
+
+    describe ".received_redis_readonly!" do
+      it "sets the right time" do
+        time = Discourse.received_redis_readonly!
+        expect(Discourse.redis_last_read_only['default']).to eq(time)
       end
     end
 
     describe ".clear_readonly!" do
       it "publishes the right message" do
-        Discourse.received_readonly!
+        Discourse.received_postgres_readonly!
         messages = []
 
         expect do
           messages = MessageBus.track_publish { Discourse.clear_readonly! }
-        end.to change { Discourse.last_read_only['default'] }.to(nil)
+        end.to change { Discourse.postgres_last_read_only['default'] }.to(nil)
 
         expect(messages.any? { |m| m.channel == Site::SITE_JSON_CHANNEL })
           .to eq(true)
diff --git a/spec/requests/forums_controller_spec.rb b/spec/requests/forums_controller_spec.rb
index c288909dd60..865e7b94845 100644
--- a/spec/requests/forums_controller_spec.rb
+++ b/spec/requests/forums_controller_spec.rb
@@ -12,7 +12,7 @@ RSpec.describe ForumsController do
     end
 
     it "returns a readonly header if the site is read only" do
-      Discourse.received_readonly!
+      Discourse.received_postgres_readonly!
       get "/srv/status"
       expect(response.status).to eq(200)
       expect(response.headers['Discourse-Readonly']).to eq('true')
diff --git a/spec/requests/topics_controller_spec.rb b/spec/requests/topics_controller_spec.rb
index d454dd9f2eb..6aac3a99ace 100644
--- a/spec/requests/topics_controller_spec.rb
+++ b/spec/requests/topics_controller_spec.rb
@@ -1762,7 +1762,7 @@ RSpec.describe TopicsController do
       end
 
       it "returns a readonly header if the site is read only" do
-        Discourse.received_readonly!
+        Discourse.received_postgres_readonly!
         get "/t/#{topic.id}.json"
         expect(response.status).to eq(200)
         expect(response.headers['Discourse-Readonly']).to eq('true')
diff --git a/spec/services/random_topic_selector_spec.rb b/spec/services/random_topic_selector_spec.rb
index c601523aebd..4f4fe5a94bb 100644
--- a/spec/services/random_topic_selector_spec.rb
+++ b/spec/services/random_topic_selector_spec.rb
@@ -16,7 +16,7 @@ describe RandomTopicSelector do
     expect(RandomTopicSelector.next(0)).to eq([])
     expect(RandomTopicSelector.next(2)).to eq([0, 1])
 
-    $redis.expects(:multi).returns(Discourse.received_readonly!)
+    $redis.expects(:multi).returns(Discourse.received_redis_readonly!)
     expect(RandomTopicSelector.next(2)).to eq([2, 3])
     $redis.unstub(:multi)