From 85212fead4eea3f00652afa2feb27abc84f372d7 Mon Sep 17 00:00:00 2001
From: Julia Kreger <juliaashleykreger@gmail.com>
Date: Tue, 4 May 2021 12:18:59 -0700
Subject: [PATCH] Add note regarding configuration drives to tuning docs

Configuraiton drives get stored in the instance_info field which
is of a text type, which in theory is not a big deal, however large
configuration drives are returned over the database client
and when entire node objects are generated by the client, which
has an obvious bandwidth and record transfer latency overhead.

Change-Id: I7f2b6ab9c3adf88202f213a42af7553cf9e8276d
---
 doc/source/admin/tuning.rst | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/doc/source/admin/tuning.rst b/doc/source/admin/tuning.rst
index c9c0744e18..1ecd1f78e5 100644
--- a/doc/source/admin/tuning.rst
+++ b/doc/source/admin/tuning.rst
@@ -215,3 +215,9 @@ use.
   wish to explore a mix of the ``direct`` deploy interface and caching
   proxies. Such a configuration can be highly beneficial in wide area
   deployments. See :ref:`Using proxies for image download <ipa-proxies>`.
+* If you're making use of large configuration drives, you may wish to ensure
+  you're using Swift to store them as opposed to housing them inside of the
+  database. The entire object and contents are returned whenever Ironic
+  needs to evaluate the entire node, which can become a performance impact.
+  For more information on configuration drives, please see
+  :ref:`Enabling the configuration drive <configdrive>`.