diff --git a/WHATS_NEW b/WHATS_NEW
index ebc58a033..cf5f8c9cc 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,8 @@
 Version 2.02.06 -
 =================================
+  Create a log header for replacement in-sync mirror log.
+  Use set_lv() and dev_set() to wipe sections of devices.
+  Add mirror_in_sync() flag to avoid unnecessary resync on activation.
   Add mirror_library description to example.conf.
   Fix uuid_from_num() buffer overrun.
   Make SIZE_SHORT the default for display_size().
diff --git a/lib/device/dev-io.c b/lib/device/dev-io.c
index a499288bb..f0fd39305 100644
--- a/lib/device/dev-io.c
+++ b/lib/device/dev-io.c
@@ -602,7 +602,7 @@ int dev_write(struct device *dev, uint64_t offset, size_t len, void *buffer)
 	return _aligned_io(&where, buffer, 1);
 }
 
-int dev_zero(struct device *dev, uint64_t offset, size_t len)
+int dev_set(struct device *dev, uint64_t offset, size_t len, int value)
 {
 	size_t s;
 	char buffer[4096];
@@ -620,7 +620,7 @@ int dev_zero(struct device *dev, uint64_t offset, size_t len)
 			  " sectors", dev_name(dev), offset >> SECTOR_SHIFT,
 			  len >> SECTOR_SHIFT);
 
-	memset(buffer, 0, sizeof(buffer));
+	memset(buffer, value, sizeof(buffer));
 	while (1) {
 		s = len > sizeof(buffer) ? sizeof(buffer) : len;
 		if (!dev_write(dev, offset, s, buffer))
diff --git a/lib/device/device.h b/lib/device/device.h
index 6a68a8fa1..4dc08e64d 100644
--- a/lib/device/device.h
+++ b/lib/device/device.h
@@ -80,7 +80,7 @@ const char *dev_name(const struct device *dev);
 int dev_read(struct device *dev, uint64_t offset, size_t len, void *buffer);
 int dev_write(struct device *dev, uint64_t offset, size_t len, void *buffer);
 int dev_append(struct device *dev, size_t len, void *buffer);
-int dev_zero(struct device *dev, uint64_t offset, size_t len);
+int dev_set(struct device *dev, uint64_t offset, size_t len, int value);
 void dev_flush(struct device *dev);
 
 struct device *dev_create_file(const char *filename, struct device *dev,
diff --git a/lib/format1/disk-rep.c b/lib/format1/disk-rep.c
index b7708819e..40d17a165 100644
--- a/lib/format1/disk-rep.c
+++ b/lib/format1/disk-rep.c
@@ -576,7 +576,7 @@ static int _write_lvs(struct disk_list *data)
 
 	pos = data->pvd.lv_on_disk.base;
 
-	if (!dev_zero(data->dev, pos, data->pvd.lv_on_disk.size)) {
+	if (!dev_set(data->dev, pos, data->pvd.lv_on_disk.size, 0)) {
 		log_error("Couldn't zero lv area on device '%s'",
 			  dev_name(data->dev));
 		return 0;
diff --git a/lib/format_text/format-text.c b/lib/format_text/format-text.c
index 4cec0142f..f831e1a47 100644
--- a/lib/format_text/format-text.c
+++ b/lib/format_text/format-text.c
@@ -1073,9 +1073,9 @@ static int _mda_setup(const struct format_type *fmt,
 		if (!add_mda(fmt, fmt->cmd->mem, mdas, pv->dev, start1,
 			     mda_size1)) return 0;
 
-		if (!dev_zero((struct device *) pv->dev, start1,
-			      (size_t) (mda_size1 >
-					wipe_size ? : mda_size1))) {
+		if (!dev_set((struct device *) pv->dev, start1,
+			     (size_t) (mda_size1 >
+				       wipe_size ? : mda_size1), 0)) {
 			log_error("Failed to wipe new metadata area");
 			return 0;
 		}
@@ -1119,9 +1119,9 @@ static int _mda_setup(const struct format_type *fmt,
 	if (mda_size2) {
 		if (!add_mda(fmt, fmt->cmd->mem, mdas, pv->dev, start2,
 			     mda_size2)) return 0;
-		if (!dev_zero(pv->dev, start2,
-			      (size_t) (mda_size1 >
-					wipe_size ? : mda_size1))) {
+		if (!dev_set(pv->dev, start2,
+			     (size_t) (mda_size1 >
+				       wipe_size ? : mda_size1), 0)) {
 			log_error("Failed to wipe new metadata area");
 			return 0;
 		}
diff --git a/lib/log/log.c b/lib/log/log.c
index 80501f97d..08673daf4 100644
--- a/lib/log/log.c
+++ b/lib/log/log.c
@@ -45,6 +45,7 @@ static int _security_level = SECURITY_LEVEL;
 static char _cmd_name[30] = "";
 static char _msg_prefix[30] = "  ";
 static int _already_logging = 0;
+static int _mirror_in_sync = 0;
 
 static lvm2_log_fn_t _lvm2_log_fn = NULL;
 
@@ -175,6 +176,11 @@ void init_security_level(int level)
 	_security_level = level;
 }
 
+void init_mirror_in_sync(int in_sync)
+{
+	_mirror_in_sync = in_sync;
+}
+
 void init_cmd_name(int status)
 {
 	_log_cmd_name = status;
@@ -239,6 +245,11 @@ int security_level()
 	return _security_level;
 }
 
+int mirror_in_sync(void)
+{
+	return _mirror_in_sync;
+}
+
 void init_debug(int level)
 {
 	_debug_level = level;
diff --git a/lib/log/log.h b/lib/log/log.h
index 7db9ea04e..e8afd4d71 100644
--- a/lib/log/log.h
+++ b/lib/log/log.h
@@ -73,6 +73,7 @@ void init_indent(int indent);
 void init_ignorelockingfailure(int level);
 void init_lockingfailed(int level);
 void init_security_level(int level);
+void init_mirror_in_sync(int in_sync);
 
 void set_cmd_name(const char *cmd_name);
 
@@ -85,6 +86,7 @@ int debug_level(void);
 int ignorelockingfailure(void);
 int lockingfailed(void);
 int security_level(void);
+int mirror_in_sync(void);
 
 /* Suppress messages to stdout/stderr (1) or everywhere (2) */
 /* Returns previous setting */
diff --git a/lib/mirror/mirrored.c b/lib/mirror/mirrored.c
index da599537d..c1abfb475 100644
--- a/lib/mirror/mirrored.c
+++ b/lib/mirror/mirrored.c
@@ -245,6 +245,9 @@ static int _add_log(struct dev_manager *dm, struct lv_segment *seg,
 		return 0;
 	}
 
+	if (mirror_in_sync() && !(seg->status & PVMOVE))
+		log_flags |= DM_NOSYNC;
+
 	if (_block_on_error_available && !(seg->status & PVMOVE))
 		log_flags |= DM_BLOCK_ON_ERROR;
 
diff --git a/tools/args.h b/tools/args.h
index 64867eaed..5967c446d 100644
--- a/tools/args.h
+++ b/tools/args.h
@@ -45,6 +45,7 @@ arg(type_ARG, '\0', "type", segtype_arg)
 arg(alloc_ARG, '\0', "alloc", alloc_arg)
 arg(separator_ARG, '\0', "separator", string_arg)
 arg(mirrorsonly_ARG, '\0', "mirrorsonly", NULL)
+arg(nosync_ARG, '\0', "nosync", NULL)
 
 /* Allow some variations */
 arg(resizable_ARG, '\0', "resizable", yes_no_arg)
diff --git a/tools/lvconvert.c b/tools/lvconvert.c
index 2e4c0ae5b..b4f10921d 100644
--- a/tools/lvconvert.c
+++ b/tools/lvconvert.c
@@ -327,7 +327,7 @@ static int lvconvert_mirrors(struct cmd_context * cmd, struct logical_volume * l
 
 			if (!(log_lv = create_mirror_log(cmd, lv->vg, ah,
 							 lp->alloc,
-							 lv->name))) {
+							 lv->name, 0))) {
 				log_error("Failed to create mirror log.");
 				return 0;
 			}
@@ -390,7 +390,7 @@ static int lvconvert_snapshot(struct cmd_context *cmd,
 
 	if (!lp->zero)
 		log_error("WARNING: \"%s\" not zeroed", lv->name);
-	else if (!zero_lv(cmd, lv)) {
+	else if (!set_lv(cmd, lv, 0)) {
 			log_error("Aborting. Failed to wipe snapshot "
 				  "exception store.");
 			return 0;
diff --git a/tools/lvcreate.c b/tools/lvcreate.c
index 23c0f3ee1..14752cdcf 100644
--- a/tools/lvcreate.c
+++ b/tools/lvcreate.c
@@ -646,7 +646,7 @@ static int _lvcreate(struct cmd_context *cmd, struct lvcreate_params *lp)
 							      lp->region_size);
 
 		if (!(log_lv = create_mirror_log(cmd, vg, ah, lp->alloc,
-						 lv_name))) {
+						 lv_name, 0))) {
 			log_error("Failed to create mirror log.");
 			return 0;
 		}
@@ -730,7 +730,7 @@ static int _lvcreate(struct cmd_context *cmd, struct lvcreate_params *lp)
 	}
 
 	if ((lp->zero || lp->snapshot) && activation()) {
-		if (!zero_lv(cmd, lv) && lp->snapshot) {
+		if (!set_lv(cmd, lv, 0) && lp->snapshot) {
 			/* FIXME Remove the failed lv we just added */
 			log_error("Aborting. Failed to wipe snapshot "
 				  "exception store. Remove new LV and retry.");
diff --git a/tools/pvcreate.c b/tools/pvcreate.c
index 9fd75719f..ddc28b198 100644
--- a/tools/pvcreate.c
+++ b/tools/pvcreate.c
@@ -96,7 +96,7 @@ static int pvcreate_check(struct cmd_context *cmd, const char *name)
 	     (yes_no_prompt("Software RAID md superblock "
 			    "detected on %s. Wipe it? [y/n] ", name) == 'y'))) {
 		log_print("Wiping software RAID md superblock on %s", name);
-		if (!dev_zero(dev, md_superblock, 4)) {
+		if (!dev_set(dev, md_superblock, 4, 0)) {
 			log_error("Failed to wipe RAID md superblock on %s",
 				  name);
 			return 0;
@@ -225,7 +225,7 @@ static int pvcreate_single(struct cmd_context *cmd, const char *pv_name,
 			goto error;
 		}
 
-		if (!dev_zero(dev, UINT64_C(0), (size_t) 2048)) {
+		if (!dev_set(dev, UINT64_C(0), (size_t) 2048, 0)) {
 			log_error("%s not wiped: aborting", pv_name);
 			dev_close(dev);
 			goto error;
diff --git a/tools/toollib.c b/tools/toollib.c
index 7afbd0c4b..4efe7d3cf 100644
--- a/tools/toollib.c
+++ b/tools/toollib.c
@@ -15,10 +15,15 @@
 
 #include "tools.h"
 #include "lv_alloc.h"
+#include "xlate.h"
 
 #include <sys/stat.h>
 #include <sys/wait.h>
 
+/* From linux/drivers/md/dm-log.c */
+#define MIRROR_MAGIC 0x4D695272
+#define MIRROR_DISK_VERSION 2
+
 /* Command line args */
 unsigned arg_count(struct cmd_context *cmd, int a)
 {
@@ -1111,9 +1116,9 @@ int generate_log_name_format(struct volume_group *vg __attribute((unused)),
 }
 
 /*
- * Volumes may be zeroed to remove old application data.
+ * Initialize the LV with 'value'.
  */
-int zero_lv(struct cmd_context *cmd, struct logical_volume *lv)
+int set_lv(struct cmd_context *cmd, struct logical_volume *lv, int value)
 {
 	struct device *dev;
 	char *name;
@@ -1126,27 +1131,80 @@ int zero_lv(struct cmd_context *cmd, struct logical_volume *lv)
 	 *	   (I know the device is at least 4k, but not 32k)
 	 */
 	if (!(name = dm_pool_alloc(cmd->mem, PATH_MAX))) {
-		log_error("Name allocation failed - device not zeroed");
+		log_error("Name allocation failed - device not cleared");
 		return 0;
 	}
 
 	if (lvm_snprintf(name, PATH_MAX, "%s%s/%s", cmd->dev_dir,
 			 lv->vg->name, lv->name) < 0) {
-		log_error("Name too long - device not zeroed (%s)", lv->name);
+		log_error("Name too long - device not cleared (%s)", lv->name);
 		return 0;
 	}
 
-	log_verbose("Zeroing start of logical volume \"%s\"", lv->name);
+	log_verbose("Clearing start of logical volume \"%s\"", lv->name);
 
 	if (!(dev = dev_cache_get(name, NULL))) {
-		log_error("%s: not found: device not zeroed", name);
+		log_error("%s: not found: device not cleared", name);
 		return 0;
 	}
 
 	if (!dev_open_quiet(dev))
 		return 0;
 
-	dev_zero(dev, UINT64_C(0), (size_t) 4096);
+	dev_set(dev, UINT64_C(0), (size_t) 4096, value);
+	dev_close_immediate(dev);
+
+	return 1;
+}
+
+
+/*
+ * This function writes a new header to the mirror log header to the lv
+ *
+ * Returns: 1 on success, 0 on failure
+ */
+static int _write_log_header(struct cmd_context *cmd, struct logical_volume *lv)
+{
+	struct device *dev;
+	char *name;
+	struct { /* The mirror log header */
+		uint32_t magic;
+		uint32_t version;
+		uint64_t nr_regions;
+	} log_header;
+
+	log_header.magic = xlate32(MIRROR_MAGIC);
+	log_header.version = xlate32(MIRROR_DISK_VERSION);
+	log_header.nr_regions = xlate64((uint64_t)-1);
+
+	if (!(name = dm_pool_alloc(cmd->mem, PATH_MAX))) {
+		log_error("Name allocation failed - log header not written (%s)",
+			lv->name);
+		return 0;
+	}
+
+	if (lvm_snprintf(name, PATH_MAX, "%s%s/%s", cmd->dev_dir,
+			 lv->vg->name, lv->name) < 0) {
+		log_error("Name too long - log header not written (%s)", lv->name);
+		return 0;
+	}
+
+	log_verbose("Writing log header to device, %s", lv->name);
+
+	if (!(dev = dev_cache_get(name, NULL))) {
+		log_error("%s: not found: log header not written", name);
+		return 0;
+	}
+
+	if (!dev_open_quiet(dev))
+		return 0;
+
+	if (!dev_write(dev, UINT64_C(0), sizeof(log_header), &log_header)) {
+		log_error("Failed to write log header to %s", name);
+		dev_close_immediate(dev);
+		return 0;
+	}
+
 	dev_close_immediate(dev);
 
 	return 1;
@@ -1156,7 +1214,8 @@ struct logical_volume *create_mirror_log(struct cmd_context *cmd,
 					 struct volume_group *vg,
 					 struct alloc_handle *ah,
 					 alloc_policy_t alloc,
-					 const char *lv_name)
+					 const char *lv_name,
+					 int in_sync)
 {
 	struct logical_volume *log_lv;
 	char *log_name;
@@ -1201,12 +1260,18 @@ struct logical_volume *create_mirror_log(struct cmd_context *cmd,
 		goto error;
 	}
 
-	if (activation() && !zero_lv(cmd, log_lv)) {
+	if (activation() && !set_lv(cmd, log_lv, in_sync)) {
 		log_error("Aborting. Failed to wipe mirror log. "
 			  "Remove new LV and retry.");
 		goto error;
 	}
 
+	if (!_write_log_header(cmd, log_lv)) {
+		log_error("Aborting. Failed to write mirror log header. "
+			  "Remove new LV and retry.");
+		goto error;
+	}
+
 	if (!deactivate_lv(cmd, log_lv)) {
 		log_error("Aborting. Failed to deactivate mirror log. "
 			  "Remove new LV and retry.");
diff --git a/tools/toollib.h b/tools/toollib.h
index 9e58d7d2a..ec9f7f07c 100644
--- a/tools/toollib.h
+++ b/tools/toollib.h
@@ -97,8 +97,9 @@ struct logical_volume *create_mirror_log(struct cmd_context *cmd,
 					 struct volume_group *vg,
 					 struct alloc_handle *ah,
 					 alloc_policy_t alloc,
-					 const char *lv_name);
+					 const char *lv_name,
+					 int in_sync);
 
-int zero_lv(struct cmd_context *cmd, struct logical_volume *lv);
+int set_lv(struct cmd_context *cmd, struct logical_volume *lv, int value);
 
 #endif