diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -626,3 +626,36 @@
 ```
   (swh) ~/swh-environment$ swh-scheduler task respawn 1
 ```
+
+
+## Starting a kafka-powered replica of the storage
+
+This repo comes with an optional `docker-compose.storage-replica.yml`
+docker compose file that can be used to test the kafka-powered replication
+mecanism for the main storage.
+
+This can be used like:
+
+```
+~/swh-environment/swh-docker-dev$ docker-compose -f docker-compose.yml -f docker-compose.storage-replica.yml up -d
+[...]
+```
+
+Compared to the original compose file, this will:
+
+- overrides the swh-storage service to activate the kafka direct writer
+  on swh.journal.objects prefixed topics using thw swh.storage.master ID,
+- overrides the swh-web service to make it use the replica instead of the
+  master storage,
+- starts a db for the replica,
+- starts a storage service based on this db,
+- starts a replayer service that runs the process that listen to kafka to
+  keeps the replica in sync.
+
+When using it, you will have a setup in which the master storage is used by
+workers and most other services, whereas the storage replica will be used to
+by the web application and should be kept in sync with the master storage
+by kafka.
+
+
+Note that the object storage is not replicated here, only the graph storage.
diff --git a/conf/storage.yml b/conf/storage-replica.yml
copy from conf/storage.yml
copy to conf/storage-replica.yml
--- a/conf/storage.yml
+++ b/conf/storage-replica.yml
@@ -1,7 +1,7 @@
 storage:
   cls: local
   args:
-    db: postgresql:///?service=swh-storage
+    db: postgresql:///?service=swh-storage-replica
     objstorage:
       cls: remote
       args:
diff --git a/conf/storage.yml b/conf/storage.yml
--- a/conf/storage.yml
+++ b/conf/storage.yml
@@ -6,3 +6,10 @@
       cls: remote
       args:
         url: http://swh-objstorage:5003/
+  journal_writer:
+    cls: kafka
+    args:
+      brokers:
+        - kafka
+      prefix: swh.journal.objects
+      client_id: swh.storage.master
diff --git a/conf/web-replica.yml b/conf/web-replica.yml
new file mode 100644
--- /dev/null
+++ b/conf/web-replica.yml
@@ -0,0 +1,41 @@
+storage:
+  cls: remote
+  args:
+    url: http://swh-storage-replica:5002/
+    timeout: 1
+
+objstorage:
+  cls: remote
+  args:
+    url: http://swh-objstorage:5003/
+
+indexer_storage:
+  cls: remote
+  args:
+    url: http://swh-idx-storage:5007/
+
+scheduler:
+  cls: remote
+  args:
+    url: http://swh-scheduler-api:5008/
+
+vault:
+  cls: remote
+  args:
+    url: http://swh-vault-api:5005/
+
+deposit:
+  private_api_url: https://swh-deposit:5006/1/private/
+  private_api_user: swhworker
+  private_api_password: ''
+
+allowed_hosts:
+  - "*"
+
+debug: yes
+
+grecaptcha:
+  activated: false
+  site_key: ''
+
+serve_assets: yes
diff --git a/docker-compose.storage-replica.yml b/docker-compose.storage-replica.yml
new file mode 100644
--- /dev/null
+++ b/docker-compose.storage-replica.yml
@@ -0,0 +1,52 @@
+version: '2'
+
+services:
+
+  # override web app to use the replica
+  swh-web:
+    environment:
+      SWH_CONFIG_FILENAME: /web-replica.yml
+    volumes:
+      - "./conf/web-replica.yml:/web-replica.yml:ro"
+    depends_on:
+      - swh-storage-replica
+
+  # create a dedicated db for the replica
+  swh-storage-replica-db:
+    image: postgres:11
+    env_file:
+      - ./env/storage-db-replica.env
+    environment:
+      # unset PGHOST as db service crashes otherwise
+      PGHOST:
+
+  # and an RPC server
+  swh-storage-replica:
+    build: ./
+    image: swh/stack
+    depends_on:
+      - swh-storage-replica-db
+      - swh-objstorage
+    env_file:
+      - ./env/storage-db-replica.env
+    environment:
+      SWH_CONFIG_FILENAME: /storage-replica.yml
+    volumes:
+      - "./conf/storage-replica.yml:/storage-replica.yml:ro"
+      - "./services/swh-storage/entrypoint.sh:/entrypoint.sh:ro"
+
+  # and the background process that keeps the replica in sync with the
+  # main graph
+  swh-storage-replica-replayer:
+    build: ./
+    image: swh/stack
+    depends_on:
+      - swh-storage-replica-db
+      - swh-objstorage
+    env_file:
+      - ./env/storage-db-replica.env
+    environment:
+      SWH_CONFIG_FILENAME: /storage-replica.yml
+    volumes:
+      - "./conf/storage-replica.yml:/storage-replica.yml:ro"
+      - "./services/swh-storage-replayer/entrypoint.sh:/entrypoint.sh:ro"
diff --git a/docker-compose.yml b/docker-compose.yml
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -149,6 +149,7 @@
     depends_on:
       - swh-storage-db
       - swh-objstorage
+      - kafka
     env_file:
       - ./env/storage-db.env
     environment:
diff --git a/env/storage-db-replica.env b/env/storage-db-replica.env
new file mode 100644
--- /dev/null
+++ b/env/storage-db-replica.env
@@ -0,0 +1,4 @@
+PGHOST=swh-storage-replica-db
+PGUSER=postgres
+POSTGRES_PASSWORD=testpassword
+POSTGRES_DB=swh-storage-replica
diff --git a/services/swh-storage-replayer/entrypoint.sh b/services/swh-storage-replayer/entrypoint.sh
new file mode 100755
--- /dev/null
+++ b/services/swh-storage-replayer/entrypoint.sh
@@ -0,0 +1,35 @@
+#!/bin/bash
+
+set -e
+
+if [[ -d /src ]] ; then
+    for srcrepo in /src/swh-* ; do
+      pushd $srcrepo
+      pip install -e .
+      popd
+    done
+fi
+
+echo Installed Python packages:
+pip list
+
+source /swh-utils/pgsql.sh
+
+setup_pgsql
+
+case "$1" in
+    "shell")
+      exec bash -i
+      ;;
+    *)
+      wait_pgsql
+
+      echo Setup the database
+      PGPASSWORD=${POSTGRES_PASSWORD} swh-db-init storage \
+          --db-name ${POSTGRES_DB}
+
+      echo Starting the swh-storage Kafka storage replayer
+      exec swh-journal replay --broker kafka --prefix swh.journal.objects \
+		   --consumer-id swh.storage.replica
+      ;;
+esac