docs: fixed database scaling docs. Fixes #4281

docs/tutorials/scaling-best-practices.rst

@@ -1,61 +1,64 b''
 .. _scaling-tips:
 
 ======================
 Scaling Best Practices
 ======================
 
-When deploying |RCE| at scale; 100s of users, multiple instances, CI servers,
+When deploying |RCE| at scale; 1000s of users, multiple instances, CI servers,
 there are a number of steps you can take to ensure you are getting the
 most out of your system.
 
 Separate Users and CI Servers
 -----------------------------
 
 You can configure multiple |RCE| instances to point to the same database and
 set of |repos|. This lets users work on an instance that has less traffic
 than those being hit by CI servers. To configure this, use |RCC| to install
 multiple instances and configure the database and |repos| connection. If you
-do need to reset the database connection, see the
+do need to reset/adjust the database connection, see the
 :ref:`config-database` section.
 
-Once configured, set your CI servers to use a particular instance and for
-user specific instances you can configure loads balancing. See the
-:ref:`nginx-ws-ref` section for examples.
+You can configure then a load-balancer to balance the traffic between the CI
+dedicated instance and instance that end users would use.
+See the :ref:`nginx-ws-ref` section for examples on how to do it in NGINX.
 
 Switch to Database Sessions
 ---------------------------
 
-To increase database performance switch to database-based user sessions. In a
-large scale deployment, we recommend switching from file-based
-sessions to database-based user sessions. For configuration details, see the
-:ref:`db-session-ref` section.
+To increase |RCE| performance switch from the default file based sessions to
+database-based. In such way all your distributed instances would not need to
+share the file storage to use file-based sessions.
+Database based session have an additional advantage of the file
+based ones that they don't need a periodic cleanup as the session library
+cleans them up for users. For configuration details,
+see the :ref:`db-session-ref` section.
 
 Tuning |RCE|
 ------------
 
 There are also a number of options available to tune |RCE| for certain
 scenarios, including memory cache size. See the :ref:`rhodecode-tuning-ref`
 section.
 
 Use Authentication Tokens
 -------------------------
 
 Set up a user account for external services, and then use Authentication
 Tokens with those external services. These tokens work with
 push/pull operations only, and you can manage multiple tokens through this user
 account, and revoke particular ones if necessary. In this way one user can have
 multiple tokens, so all your jenkins/CI servers could share one account.
 
 * To enable tokens, go to :menuselection:`Admin --> Authentication` and enable
   the `rhodecode.lib.auth_modules.auth_token` library.
 
 * To create tokens, go to
   :menuselection:`Username --> My Account --> Auth tokens` and generate the
   necessary tokens. For more information, see the :ref:`config-token-ref`
   section.
 
 Scaling Deployment Diagram
 --------------------------
 
 .. image:: ../images/scaling-diagrm.png
    :align: center