doc(1.8.0): add replica auto-balance to best-practice

Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

content/docs/1.8.0/best-practices.md

@@ -217,3 +217,13 @@ This setting should be set to `false` in production environment to ensure the be
 > Recommend: `false`
 
 This setting should be set to `false` in production environment to ensure every volume have the best availability when created. Because with the setting set to `true`, the volume creation won't error out even there is only enough room to schedule one replica. So there is a risk that the cluster is running out of the spaces but the user won't be made aware immediately.
+
+### Replica Auto-Balance
+
+> Recommend: `least-effort`
+
+For production environments, we recommend to set Replica Auto-Balance to `least-effort`. This setting ensures that at least one replica is placed on a different node and in each zone, providing extra high availablity (HA).
+
+In certain edge cases, you might consider using the `best-effort`, which continuously attempts to evenly distribute replicas across nodes and zones. However, this setting can lead to frequent rebuilds if the cluster is unstable.
+
+For most users, having multiple replicas without Replica Auto-Balance setting is sufficient to achieve basic HA, especially if you prefer to avoid excessive rebuilds.