diff --git a/Erasure-Coding-for-warm-storage.md b/Erasure-Coding-for-warm-storage.md
index 5041749..b5ea1cb 100644
--- a/Erasure-Coding-for-warm-storage.md
+++ b/Erasure-Coding-for-warm-storage.md
@@ -38,6 +38,8 @@ The scripts have 3 steps related to erasure coding.
 
 The default command is `ec.encode -fullPercent=95 -quietFor=1h`. It will find volumes at least 95% of the maximum volume size, which is usually 30GB, and have no updates for 1 hour.
 
+Note: One collection can contain both normal volumes and erasure coded volumes, with write requests going to normal volumes.
+
 ### Data Repair
 If disks fail or servers fail, some data shards are lost. With erasure coding, we can recover the lost data shards from the remaining data shards.