+.BR -b , --block
+Block access to the file by other applications during data migration
+(default). This prevents other processes from accessing the file during
+migration, which prevents data data writes to the old file objects from
+being lost. This should be used if an OST needs to be completely emptied
+prior to its removal, to ensure all requested files are migrated off the
+OST.
+.TP
+.BR -n , --non-block
+Abort migration if concurrent file access is detected. This can be
+used with OST space balancing migration to avoid interfering with file
+access by applications if there is not a requirement to migrate any
+particular file to the new layout.
+.TP
+.BR -D , --non-direct
+Do
+.B not
+use
+.B O_DIRECT
+read and write operations when migrating a file. The
+.B O_DIRECT
+option avoids data copy from kernel buffers into userspace, which can
+impose CPU and memory overhead on the copy operation, but makes read and
+write operations synchronous. Using the
+.B --non-direct
+option uses buffered read/write operations, which may improve migration
+speed at the cost of more CPU and memory overhead.
+.P
+NOTE:
+.B lfs migrate
+has a complementary
+.B lfs_migrate
+script which is used to provide extra functionality when migrating file
+data between OSTs and has a separate man page. See
+.BR lfs_migrate (1)
+for details.
+.SH MDT MIGRATE OPTIONS
+.TP
+.RB -m , --mdt-index
+Causes the file metadata (inode) to be migrated to the MDT with index
+.IR mdt_idx .
+This is useful if new MDTs have been added to a filesystem and existing
+user or project directories should be migrated off old MDTs to balance
+the space usage and future metadata workload.
+.P