diff --git a/Tiered-Storage.md b/Tiered-Storage.md
index 1be4b89..cdf4cfd 100644
--- a/Tiered-Storage.md
+++ b/Tiered-Storage.md
@@ -7,7 +7,7 @@ To write any data, the volume index needs to append one entry. To read any data,
 
 You can run `weed volume -dir.idx=/fast/disk/dir` or `weed server -volume.dir.idx=/vast/disk/dir` to ensure the volume index is located on a fast disk, e.g., a fast SSD mount.
 
-# Volume Disk Type
+# SSD & HDD Volume Disk Types
 
 If the volume data also needs fast access, you can create them on fast disks.
 
@@ -27,5 +27,8 @@ fs.configure -locationPrefix=/buckets/ssd_ -disk=ssd -apply
 
 https://github.com/chrislusf/seaweedfs/wiki/Path-Specific-Configuration
 
-For now, an ssd volume needs to be manually moved from ssd directory to hdd directory, if you want to change the disk type of a volume.
+## Notes
 
+When `volume.balance`, `volume.fix.replication`, or `volume.move`, the volume disk type would not change.
+
+For now, if you want to change the disk type of a volume, the volume needs to be manually moved from ssd directory to hdd directory, or vice versa.
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