diff --git a/utils/src/format.h b/utils/src/format.h
index d46b2195..be2931dc 100644
--- a/utils/src/format.h
+++ b/utils/src/format.h
@@ -272,6 +272,14 @@ struct scoutfs_extent_btree_key {
 	__be64 minor;
 } __packed;
 
+/*
+ * The lock server keeps a persistent record of connected clients so that
+ * server failover knows who to wait for before resuming operations.
+ */
+struct scoutfs_lock_client_btree_key {
+	__be64 node_id;
+} __packed;
+
 /*
  * The max number of links defines the max number of entries that we can
  * index in o(log n) and the static list head storage size in the
@@ -456,6 +464,7 @@ struct scoutfs_super_block {
 	struct scoutfs_btree_root alloc_root;
 	struct scoutfs_manifest manifest;
 	struct scoutfs_quorum_config quorum_config;
+	struct scoutfs_btree_root lock_clients;
 } __packed;
 
 #define SCOUTFS_ROOT_INO 1
@@ -642,6 +651,7 @@ enum {
 	SCOUTFS_NET_CMD_STATFS,
 	SCOUTFS_NET_CMD_COMPACT,
 	SCOUTFS_NET_CMD_LOCK,
+	SCOUTFS_NET_CMD_LOCK_RECOVER,
 	SCOUTFS_NET_CMD_FAREWELL,
 	SCOUTFS_NET_CMD_UNKNOWN,
 };
@@ -768,6 +778,15 @@ struct scoutfs_net_lock {
 	__u8 new_mode;
 } __packed;
 
+struct scoutfs_net_lock_recover {
+	__le16 nr;
+	struct scoutfs_net_lock locks[0];
+} __packed;
+
+#define SCOUTFS_NET_LOCK_MAX_RECOVER_NR					       \
+	((SCOUTFS_NET_MAX_DATA_LEN - sizeof(struct scoutfs_net_lock_recover)) /\
+	 sizeof(struct scoutfs_net_lock))
+
 /* some enums for tracing */
 enum {
 	SLT_CLIENT,
diff --git a/utils/src/print.c b/utils/src/print.c
index e697b40b..896cf83b 100644
--- a/utils/src/print.c
+++ b/utils/src/print.c
@@ -343,6 +343,16 @@ static int print_alloc_item(void *key, unsigned key_len, void *val,
 	return 0;
 }
 
+static int print_lock_clients_entry(void *key, unsigned key_len, void *val,
+				    unsigned val_len, void *arg)
+{
+	struct scoutfs_lock_client_btree_key *cbk = key;
+
+	printf("    node_ld %llu\n", be64_to_cpu(cbk->node_id));
+
+	return 0;
+}
+
 typedef int (*print_item_func)(void *key, unsigned key_len, void *val,
 			       unsigned val_len, void *arg);
 
@@ -522,6 +532,7 @@ static void print_super_block(struct scoutfs_super_block *super, u64 blkno)
 	       "  total_blocks %llu free_blocks %llu alloc_cursor %llu\n"
 	       "  btree ring: first_blkno %llu nr_blocks %llu next_block %llu "
 	       "next_seq %llu\n"
+	       "  lock_clients root: height %u blkno %llu seq %llu mig_len %u\n"
 	       "  alloc btree root: height %u blkno %llu seq %llu mig_len %u\n"
 	       "  manifest btree root: height %u blkno %llu seq %llu mig_len %u\n",
 		le64_to_cpu(super->next_ino),
@@ -536,6 +547,10 @@ static void print_super_block(struct scoutfs_super_block *super, u64 blkno)
 		le64_to_cpu(super->bring.nr_blocks),
 		le64_to_cpu(super->bring.next_block),
 		le64_to_cpu(super->bring.next_seq),
+		super->lock_clients.height,
+		le64_to_cpu(super->lock_clients.ref.blkno),
+		le64_to_cpu(super->lock_clients.ref.seq),
+		le16_to_cpu(super->lock_clients.migration_key_len),
 		super->alloc_root.height,
 		le64_to_cpu(super->alloc_root.ref.blkno),
 		le64_to_cpu(super->alloc_root.ref.seq),
@@ -595,6 +610,11 @@ static int print_volume(int fd)
 
 	ret = print_quorum_blocks(fd, super);
 
+	err = print_btree(fd, super, "lock_clients", &super->lock_clients,
+			  print_lock_clients_entry, NULL);
+	if (err && !ret)
+		ret = err;
+
 	err = print_btree(fd, super, "alloc", &super->alloc_root,
   			  print_alloc_item, NULL);
 	if (err && !ret)