[PATCH mdadm v4 7/7] manpage: Add --write-zeroes option to manpage

[Logan Gunthorpe <logang@deltatee.com>]

Document the new --write-zeroes option in the manpage.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
 mdadm.8.in | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/mdadm.8.in b/mdadm.8.in
index 70c79d1e6e76..3beb475fd955 100644
--- a/mdadm.8.in
+++ b/mdadm.8.in
@@ -837,6 +837,22 @@ array is resynced at creation.  From Linux version 3.0,
 .B \-\-assume\-clean
 can be used with that command to avoid the automatic resync.
 
+.TP
+.BR \-\-write-zeroes
+When creating an array, send write zeroes requests to all the block
+devices.  This should zero the data area on all disks such that the
+initial sync is not necessary and, if successfull, will behave
+as if
+.B \-\-assume\-clean
+was specified.
+.IP
+This is intended for use with devices that have hardware offload for
+zeroing, but despit this zeroing can still take several minutes for
+large disks.  Thus a message is printed before and after zeroing and
+each disk is zeroed in parallel with the others.
+.IP
+This is only meaningful with --create.
+
 .TP
 .BR \-\-backup\-file=
 This is needed when
-- 
2.30.2