diff --git a/tools/storage_mon.c b/tools/storage_mon.c
index 27d2ff1d1..6c4555f04 100644
--- a/tools/storage_mon.c
+++ b/tools/storage_mon.c
@@ -119,6 +119,8 @@ static void *test_device(const char *device, int verbose, int inject_error_perce
 	int device_fd;
 	int res;
 	off_t seek_spot;
+	int sec_size = 512;
+	void *buffer;
 
 	if (verbose) {
 		printf("Testing device %s\n", device);
@@ -150,23 +152,7 @@ static void *test_device(const char *device, int verbose, int inject_error_perce
 		PRINT_STORAGE_MON_INFO("%s: opened %s O_DIRECT, size=%zu", device, (flags & O_DIRECT)?"with":"without", devsize);
 	}
 
-	/* Don't fret about real randomness */
-	srand(time(NULL) + getpid());
-	/* Pick a random place on the device - sector aligned */
-	seek_spot = (rand() % (devsize-1024)) & 0xFFFFFFFFFFFFFE00;
-	res = lseek(device_fd, seek_spot, SEEK_SET);
-	if (res < 0) {
-		PRINT_STORAGE_MON_ERR("Failed to seek %s: %s", device, strerror(errno));
-		goto error;
-	}
-	if (verbose) {
-		PRINT_STORAGE_MON_INFO("%s: reading from pos %ld", device, seek_spot);
-	}
-
 	if (flags & O_DIRECT) {
-		int sec_size = 0;
-		void *buffer;
-
 #ifdef __FreeBSD__
 		res = ioctl(device_fd, DIOCGSECTORSIZE, &sec_size);
 #else
@@ -176,33 +162,34 @@ static void *test_device(const char *device, int verbose, int inject_error_perce
 			PRINT_STORAGE_MON_ERR("Failed to get block device sector size for %s: %s", device, strerror(errno));
 			goto error;
 		}
+	}
 
-		if (posix_memalign(&buffer, sysconf(_SC_PAGESIZE), sec_size) != 0) {
-			PRINT_STORAGE_MON_ERR("Failed to allocate aligned memory: %s", strerror(errno));
-			goto error;
-		}
-		res = read(device_fd, buffer, sec_size);
-		free(buffer);
-		if (res < 0) {
-			PRINT_STORAGE_MON_ERR("Failed to read %s: %s", device, strerror(errno));
-			goto error;
-		}
-		if (res < sec_size) {
-			PRINT_STORAGE_MON_ERR("Failed to read %d bytes from %s, got %d", sec_size, device, res);
-			goto error;
-		}
-	} else {
-		char buffer[512];
+	/* Don't fret about real randomness */
+	srand(time(NULL) + getpid());
+	/* Pick a random place on the device - sector aligned */
+	seek_spot = (rand() % (devsize-sec_size)) & ~(((off_t) sec_size)-1);
+	res = lseek(device_fd, seek_spot, SEEK_SET);
+	if (res < 0) {
+		PRINT_STORAGE_MON_ERR("Failed to seek %s: %s", device, strerror(errno));
+		goto error;
+	}
+	if (verbose) {
+		PRINT_STORAGE_MON_INFO("%s: reading from pos %ld", device, seek_spot);
+	}
 
-		res = read(device_fd, buffer, sizeof(buffer));
-		if (res < 0) {
-			PRINT_STORAGE_MON_ERR("Failed to read %s: %s", device, strerror(errno));
-			goto error;
-		}
-		if (res < (int)sizeof(buffer)) {
-			PRINT_STORAGE_MON_ERR("Failed to read %ld bytes from %s, got %d", sizeof(buffer), device, res);
-			goto error;
-		}
+	if (posix_memalign(&buffer, sysconf(_SC_PAGESIZE), sec_size) != 0) {
+		PRINT_STORAGE_MON_ERR("Failed to allocate aligned memory: %s", strerror(errno));
+		goto error;
+	}
+	res = read(device_fd, buffer, sec_size);
+	free(buffer);
+	if (res < 0) {
+		PRINT_STORAGE_MON_ERR("Failed to read %s: %s", device, strerror(errno));
+		goto error;
+	}
+	if (res < sec_size) {
+		PRINT_STORAGE_MON_ERR("Failed to read %d bytes from %s, got %d", sec_size, device, res);
+		goto error;
 	}
 
 	/* Fake an error */