Added information about configuring faster storage for etcd

Author: ahardin-rh

modules/installation-aws-config-yaml.adoc

@@ -26,17 +26,21 @@ controlPlane: <2>
       zones:
       - us-west-2a
       - us-west-2b
+      rootVolume:
+        iops: 4000
+        size: 500
+        type: io1
       type: m5.xlarge
   replicas: 3
 compute: <2>
 - name: worker
   platform:
     aws:
       rootVolume:
-        iops: 4000
+        iops: 2000
         size: 500
-        type: io1
-      type: c5.9xlarge
+        type: io1 <4>
+      type: c5.4xlarge
       zones:
       - us-west-2c
   replicas: 5
@@ -62,4 +66,6 @@ sshKey: ssh-ed25519 AAAA... <3>
 <2> If you do not provide these parameters and values, the installation program
 provides the default value.
 <3> You can optionally provide the `sshKey` value that you use to access the
-machines in your cluster.
+machines in your cluster.
+<4> To configure faster storage for etcd, especially for larger clusters, set the
+storage type as `io1` and set `iops` to `2000`.