1 files changed, 3 insertions, 0 deletions
diff --git a/mdadm.8.in b/mdadm.8.in
index d9b51473..3fbfcce8 100644
--- a/mdadm.8.in
+++ b/mdadm.8.in
@@ -484,6 +484,9 @@ array is 512KB.  To ensure compatibility with earlier versions, the
 default when Building and array with no persistent metadata is 64KB.
 This is only meaningful for RAID0, RAID4, RAID5, RAID6, and RAID10.
 
+RAID4, RAID5, RAID6, and RAID10 require the chunk size to be a power
+of 2.  In any case it must be a multiple of 4KB.
+
 A suffix of 'M' or 'G' can be given to indicate Megabytes or
 Gigabytes respectively.