diff --git a/cmdline/parity.c b/cmdline/parity.c
index b590d6b5..382894d4 100644
--- a/cmdline/parity.c
+++ b/cmdline/parity.c
@@ -893,8 +893,27 @@ int parity_sync(struct snapraid_parity_handle* handle)
 		 * Ensure that data changes are written to disk.
 		 * This is required to ensure that parity is more updated than content
 		 * in case of a system crash.
+		 *
+		 * On macOS, standard fsync() only pushes data from kernel buffers to the
+		 * drive's volatile cache without requesting a physical media flush. F_FULLFSYNC
+		 * forces the drive controller to commit all cached data to permanent storage.
+		 * Because F_FULLFSYNC is not supported on directory descriptors, the subsequent
+		 * directory fsync() only flushes to the drive cache and is not guaranteed to be
+		 * instantly persistent across power loss. However, major database engines such
+		 * as SQLite and PostgreSQL follow this exact same pattern on Darwin, making it
+		 * the standard industry practice.
+		 *
+		 * See:
+		 * https://github.com/sqlite/sqlite/blob/f3b9f74d81132426dee1ccc07a67fdad2ccfeaa9/src/os_unix.c#L3928-L3953
+		 * https://github.com/postgres/postgres/blob/74c77052bc20017076100f0649ca0f44b1b98c29/src/backend/storage/file/fd.c#L835-L852
 		 */
+#if defined(__APPLE__) && defined(F_FULLFSYNC)
+		ret = fcntl(split->f, F_FULLFSYNC);
+		if (ret != 0 && (errno == ENOTSUP || errno == EINVAL))
+			ret = fsync(split->f);
+#else
 		ret = fsync(split->f);
+#endif
 		if (ret != 0) {
 			/* LCOV_EXCL_START */
 			log_fatal(errno, "Error syncing parity file '%s'. %s.\n", split->path, strerror(errno));
diff --git a/cmdline/state.c b/cmdline/state.c
index 33c553c3..1fbc564b 100644
--- a/cmdline/state.c
+++ b/cmdline/state.c
@@ -5108,7 +5108,8 @@ static void state_rename_content(struct snapraid_state* state)
 	/*
 	 * This sequence relies on POSIX file-system semantics.
 	 *
-	 * The temporary content file has already been flushed and fsync'ed.
+	 * The temporary content file has already been flushed and fsync'ed in
+	 * ssync() (using F_FULLFSYNC on macOS to force a physical media flush).
 	 * rename()/renameat() atomically replaces the old content file, but the
 	 * directory entry update is not necessarily durable when the rename
 	 * returns.
@@ -5119,6 +5120,19 @@ static void state_rename_content(struct snapraid_state* state)
 	 * may start only after the pre-sync content state has been durably
 	 * published.
 	 *
+	 * On macOS, standard fsync() only pushes data from kernel buffers to the
+	 * drive's volatile cache without requesting a physical media flush. F_FULLFSYNC
+	 * forces the drive controller to commit all cached data to permanent storage.
+	 * Because F_FULLFSYNC is not supported on directory descriptors, the subsequent
+	 * directory fsync() only flushes to the drive cache and is not guaranteed to be
+	 * instantly persistent across power loss. However, major database engines such
+	 * as SQLite and PostgreSQL follow this exact same pattern on Darwin, making it
+	 * the standard industry practice.
+	 *
+	 * See:
+	 * https://github.com/sqlite/sqlite/blob/f3b9f74d81132426dee1ccc07a67fdad2ccfeaa9/src/os_unix.c#L3928-L3953
+	 * https://github.com/postgres/postgres/blob/74c77052bc20017076100f0649ca0f44b1b98c29/src/backend/storage/file/fd.c#L835-L852
+	 *
 	 * When renameat() is available, perform the rename relative to the same
 	 * directory descriptor that is subsequently fsync'ed. Use O_DIRECTORY
 	 * when available, while retaining compatibility with POSIX systems where
diff --git a/cmdline/stream.c b/cmdline/stream.c
index 1b56b9a8..81003ff5 100644
--- a/cmdline/stream.c
+++ b/cmdline/stream.c
@@ -835,7 +835,21 @@ int ssync(STREAM* s)
 	unsigned i;
 
 	for (i = 0; i < s->handle_size; ++i) {
-		if (fsync(s->handle[i].f) != 0) {
+		int ret;
+
+		/*
+		 * On macOS, standard fsync() only pushes data from kernel buffers to the
+		 * drive's volatile cache without requesting a physical media flush. F_FULLFSYNC
+		 * forces the drive controller to commit all cached data to permanent storage.
+		 */
+#if defined(__APPLE__) && defined(F_FULLFSYNC)
+		ret = fcntl(s->handle[i].f, F_FULLFSYNC);
+		if (ret != 0 && (errno == ENOTSUP || errno == EINVAL))
+			ret = fsync(s->handle[i].f);
+#else
+		ret = fsync(s->handle[i].f);
+#endif
+		if (ret != 0) {
 			/* LCOV_EXCL_START */
 			s->state = STREAM_STATE_ERROR;
 			s->state_index = i;