Merge pull request #58579 from lahinson/ocpbugs-9060-etcd-encryption-warning

[OCPBUGS-9060]: Adding warning to etcd encryption docs

Author: jab-rh

modules/enabling-etcd-encryption.adoc

@@ -11,7 +11,13 @@ You can enable etcd encryption to encrypt sensitive resources in your cluster.
 
 [WARNING]
 ====
-It is not recommended to take a backup of etcd until the initial encryption process is complete. If the encryption process has not completed, the backup might be only partially encrypted.
+Do not back up etcd resources until the initial encryption process is completed. If the encryption process is not completed, the backup might be only partially encrypted.
+
+After you enable etcd encryption, several changes can occur:
+
+* The etcd encryption might affect the memory consumption of a few resources.
+* You might notice a transient affect on backup performance because the leader must serve the backup.
+* A disk I/O can affect the node that receives the backup state.
 ====
 
 .Prerequisites
@@ -27,15 +33,15 @@ It is not recommended to take a backup of etcd until the initial encryption proc
 $ oc edit apiserver
 ----
 
-. Set the `encryption` field to `aescbc` or `aesgcm`:
+. Set the `encryption` field type to `aescbc`:
 +
 [source,yaml]
 ----
 spec:
   encryption:
     type: aescbc <1>
 ----
-<1> Set to `aescbc` for AES-CBC encryption or `aesgcm` for AES-GCM encryption.
+<1> The `aescbc` type means that AES-CBC with PKCS#7 padding and a 32 byte key is used to perform the encryption.
 
 . Save the file to apply the changes.
 +