From: François Tigeot <ftigeot@wolfpond.org>
Date: Wed, 18 Jan 2012 09:36:56 +0000 (+0100)
Subject: Disable HAMMER live dedup, mark as experimental
X-Git-Tag: v3.0.0~35
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/6de803f0514ff0019181d026a825d1e8a9a4c404

Disable HAMMER live dedup, mark as experimental

* Comment out mentions to it in the hammer(8) manpage

* Live-dedup is a relatively new feature that has not undergone
  extensive testing.

* It may have some issues with HAMMER bigblocks, we do not want
  users to run it on production machines yet.
---

diff --git a/sbin/hammer/hammer.8 b/sbin/hammer/hammer.8
index a662f19bdf..e85d881948 100644
--- a/sbin/hammer/hammer.8
+++ b/sbin/hammer/hammer.8
@@ -1513,14 +1513,14 @@ The swapcache will save the cached VM pages related to
 block
 device (which doesn't recycle unless you umount the filesystem) instead
 of the cached VM pages backing the file vnodes.
-.Pp
-Double buffering should also be turned on if live dedup is enabled via
-.Va vfs.hammer.live_dedup .
-This is because the live dedup must validate the contents of a potential
-duplicate file block and it must run through the block device to do that
-and not the file vnode.
-If double buffering is not enabled then live dedup will create extra disk
-reads to validate potential data duplicates.
+.\".Pp
+.\"Double buffering should also be turned on if live dedup is enabled via
+.\"Va vfs.hammer.live_dedup .
+.\"This is because the live dedup must validate the contents of a potential
+.\"duplicate file block and it must run through the block device to do that
+.\"and not the file vnode.
+.\"If double buffering is not enabled then live dedup will create extra disk
+.\"reads to validate potential data duplicates.
 .Sh UPGRADE INSTRUCTIONS HAMMER V1 TO V2
 This upgrade changes the way directory entries are stored.
 It is possible to upgrade a V1 file system to V2 in place, but
diff --git a/sys/vfs/hammer/hammer_vfsops.c b/sys/vfs/hammer/hammer_vfsops.c
index 4b6103e40d..03049b3161 100644
--- a/sys/vfs/hammer/hammer_vfsops.c
+++ b/sys/vfs/hammer/hammer_vfsops.c
@@ -158,8 +158,8 @@ SYSCTL_INT(_vfs_hammer, OID_AUTO, cluster_enable, CTLFLAG_RW,
  * 1 - dedup cache is populated on reads only
  * 2 - dedup cache is populated on both reads and writes
  */
-SYSCTL_INT(_vfs_hammer, OID_AUTO, live_dedup, CTLFLAG_RW,
-	   &hammer_live_dedup, 0, "Enable live dedup");
+SYSCTL_INT(_vfs_hammer, OID_AUTO, live_dedup, CTLFLAG_RD,
+	   &hammer_live_dedup, 0, "Enable live dedup (experimental)");
 SYSCTL_INT(_vfs_hammer, OID_AUTO, tdmux_ticks, CTLFLAG_RW,
 	   &hammer_tdmux_ticks, 0, "Hammer tdmux ticks");