From cdefd8635de24200b55822fa0b6bc23a638fb87a Mon Sep 17 00:00:00 2001
From: David Teigland <teigland@redhat.com>
Date: Mon, 21 Feb 2022 11:35:58 -0600
Subject: [PATCH 33/54] man lvmcache: mention writecache memory usage

---
 man/lvmcache.7_main | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/man/lvmcache.7_main b/man/lvmcache.7_main
index 48cf7b492..73680235b 100644
--- a/man/lvmcache.7_main
+++ b/man/lvmcache.7_main
@@ -240,6 +240,18 @@ The writecache block size should be chosen to match the xfs sectsz value.
 It is also possible to specify a sector size of 4096 to mkfs.xfs when
 creating the file system.  In this case the writecache block size of 4096
 can be used.
+.P
+.SS dm-writecache memory usage
+.P
+The amount of main system memory used by dm-writecache can be a factor
+when selecting the writecache cachevol size and the writecache block size.
+.P
+.IP \[bu] 2
+writecache block size 4096: each 100 GiB of writecache cachevol uses
+slighly over 2 GiB of system memory.
+.IP \[bu] 2
+writecache block size 512: each 100 GiB of writecache cachevol uses
+a little over 16 GiB of system memory.
 .
 .SS dm-writecache settings
 .
-- 
2.34.3