Add option none to zfs redundant_metadata property

Currently, additional/extra copies are created for metadata in addition to the redundancy provided by the pool(mirror/raidz/draid), due to this 2 times more space is utilized per inode and this decreases the total number of inodes that can be created in the filesystem. By setting redundant_metadata to none, no additional copies of metadata are created, hence can reduce the space consumed by the additional metadata copies and increase the total number of inodes that can be created in the filesystem. Reviewed-by: Dipak Ghosh <[email protected]> Signed-off-by: Akash B <[email protected]>
openzfs · Jul 20, 2022 · 33f301b · 33f301b
1 parent f371cc1
commit 33f301b
Show file tree

Hide file tree

Showing 4 changed files with 10 additions and 5 deletions.
diff --git a/include/sys/fs/zfs.h b/include/sys/fs/zfs.h
@@ -500,7 +500,8 @@ typedef enum {
 
 typedef enum {
 	ZFS_REDUNDANT_METADATA_ALL,
-	ZFS_REDUNDANT_METADATA_MOST
+	ZFS_REDUNDANT_METADATA_MOST,
+	ZFS_REDUNDANT_METADATA_NONE
 } zfs_redundant_metadata_type_t;
 
 typedef enum {

diff --git a/module/zcommon/zfs_prop.c b/module/zcommon/zfs_prop.c
@@ -369,6 +369,7 @@ zfs_prop_init(void)
 	static const zprop_index_t redundant_metadata_table[] = {
 		{ "all",	ZFS_REDUNDANT_METADATA_ALL },
 		{ "most",	ZFS_REDUNDANT_METADATA_MOST },
+		{ "none",	ZFS_REDUNDANT_METADATA_NONE },
 		{ NULL }
 	};
 
@@ -388,7 +389,7 @@ zfs_prop_init(void)
 	zprop_register_index(ZFS_PROP_REDUNDANT_METADATA, "redundant_metadata",
 	    ZFS_REDUNDANT_METADATA_ALL,
 	    PROP_INHERIT, ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME,
-	    "all | most", "REDUND_MD",
+	    "all | most | none", "REDUND_MD",
 	    redundant_metadata_table, sfeatures);
 	zprop_register_index(ZFS_PROP_SYNC, "sync", ZFS_SYNC_STANDARD,
 	    PROP_INHERIT, ZFS_TYPE_FILESYSTEM | ZFS_TYPE_VOLUME,

diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c
@@ -1989,11 +1989,13 @@ dmu_write_policy(objset_t *os, dnode_t *dn, int level, int wp, zio_prop_t *zp)
 		    ZCHECKSUM_FLAG_EMBEDDED))
 			checksum = ZIO_CHECKSUM_FLETCHER_4;
 
-		if (os->os_redundant_metadata == ZFS_REDUNDANT_METADATA_ALL ||
+		if ((os->os_redundant_metadata !=
+		    ZFS_REDUNDANT_METADATA_NONE &&
+		    (os->os_redundant_metadata == ZFS_REDUNDANT_METADATA_ALL ||
 		    (os->os_redundant_metadata ==
 		    ZFS_REDUNDANT_METADATA_MOST &&
 		    (level >= zfs_redundant_metadata_most_ditto_level ||
-		    DMU_OT_IS_METADATA(type) || (wp & WP_SPILL))))
+		    DMU_OT_IS_METADATA(type) || (wp & WP_SPILL))))))
 			copies++;
 	} else if (wp & WP_NOFILL) {
 		ASSERT(level == 0);

diff --git a/module/zfs/dmu_objset.c b/module/zfs/dmu_objset.c
@@ -287,7 +287,8 @@ redundant_metadata_changed_cb(void *arg, uint64_t newval)
 	 * Inheritance and range checking should have been done by now.
 	 */
 	ASSERT(newval == ZFS_REDUNDANT_METADATA_ALL ||
-	    newval == ZFS_REDUNDANT_METADATA_MOST);
+	    newval == ZFS_REDUNDANT_METADATA_MOST ||
+	    newval == ZFS_REDUNDANT_METADATA_NONE);
 
 	os->os_redundant_metadata = newval;
 }