Slightly improve gjournal documentation.

Reviewed by:	pjd

sbin/geom/class/journal/gjournal.8

@@ -162,7 +162,8 @@ Hardcode provider names in metadata.
 Specifies size of the journal if only one provider is used for both data and
 journal.
 The default is one gigabyte.
-Size should be chosen based on provider's load, and not on its size.
+Size should be chosen based on provider's load, and not on its size;
+recommended minimum is twice the size of the physical memory installed.
 It is not recommended to use
 .Nm
 for small file systems (e.g.: only few gigabytes big).

sbin/newfs/newfs.8

@@ -85,6 +85,9 @@ wear levelling algorithms.
 NB: Erasing may take as long time as writing every sector on the disk.
 .It Fl J
 Enable journaling on the new file system via gjournal.
+See
+.Xr gjournal 8
+for details.
 .It Fl L Ar volname
 Add a volume label to the new file system.
 .It Fl N
@@ -278,6 +281,7 @@ on file systems that contain many small files.
 .Xr dump 8 ,
 .Xr dumpfs 8 ,
 .Xr fsck 8 ,
+.Xr gjournal 8 ,
 .Xr mount 8 ,
 .Xr tunefs 8 ,
 .Xr gvinum 8

sbin/tunefs/tunefs.8

@@ -89,7 +89,7 @@ this parameter should be set higher.
 .It Fl f Ar avgfilesize
 Specify the expected average file size.
 .It Fl J Cm enable | disable
-Turn on/off GJournal flag.
+Turn on/off gjournal flag.
 .It Fl L Ar volname
 Add/modify an optional file system volume label.
 .It Fl l Cm enable | disable
@@ -145,6 +145,7 @@ specified mount point.
 .Sh SEE ALSO
 .Xr fs 5 ,
 .Xr dumpfs 8 ,
+.Xr gjournal 8 ,
 .Xr newfs 8
 .Rs
 .%A M. McKusick