Fix confusing usage in md.4 man page.

"degraded write performance" could be confused with "write performance
when degraded".  It really means "reduced write performance", so say
that.

1 files changed, 1 insertions, 1 deletions

diff --git a/md.4 b/md.4
index af1a7968..dfd287f1 100644
--- a/md.4
+++ b/md.4
@@ -240,7 +240,7 @@ across a later section of all drives, always ensuring that all copies
 of any given block are on different drives.
 
 The 'far' arrangement can give sequential read performance equal to
-that of a RAID0 array, but at the cost of degraded write performance.
+that of a RAID0 array, but at the cost of reduced write performance.
 
 When 'offset' replicas are chosen, the multiple copies of a given
 chunk are laid out on consecutive drives and at consecutive offsets.