diff --git a/lib/ftl/ftl_band.h b/lib/ftl/ftl_band.h
index cba5e709a..82dabe3d1 100644
--- a/lib/ftl/ftl_band.h
+++ b/lib/ftl/ftl_band.h
@@ -64,6 +64,9 @@ struct ftl_band_md {
 	/* nv_cache p2l md region associated with band */
 	enum ftl_layout_region_type	p2l_md_region;
 
+	/* Reserved */
+	uint8_t				reserved[4];
+
 	/* Sequence ID when band was opened */
 	uint64_t			seq;
 
@@ -78,7 +81,10 @@ struct ftl_band_md {
 
 	/* CRC32 checksum of the associated P2L map when band is in closed state */
 	uint32_t			p2l_map_checksum;
-} __attribute__((aligned(FTL_BLOCK_SIZE)));
+
+	/* Reserved */
+	uint8_t				reserved2[4028];
+} __attribute__((packed));
 
 SPDK_STATIC_ASSERT(sizeof(struct ftl_band_md) == FTL_BLOCK_SIZE, "Incorrect metadata size");
 
diff --git a/lib/ftl/ftl_nv_cache.h b/lib/ftl/ftl_nv_cache.h
index c32fc413d..d68493985 100644
--- a/lib/ftl/ftl_nv_cache.h
+++ b/lib/ftl/ftl_nv_cache.h
@@ -83,7 +83,10 @@ struct ftl_nv_cache_chunk_md {
 
 	/* CRC32 checksum of the associated P2L map when chunk is in closed state */
 	uint32_t p2l_map_checksum;
-} __attribute__((aligned(FTL_BLOCK_SIZE)));
+
+	/* Reserved */
+	uint8_t reserved[4052];
+} __attribute__((packed));
 
 #define FTL_NV_CACHE_CHUNK_MD_SIZE sizeof(struct ftl_nv_cache_chunk_md)
 SPDK_STATIC_ASSERT(FTL_NV_CACHE_CHUNK_MD_SIZE == FTL_BLOCK_SIZE,
diff --git a/lib/ftl/ftl_sb_common.h b/lib/ftl/ftl_sb_common.h
index c667e288b..d0b26bed4 100644
--- a/lib/ftl/ftl_sb_common.h
+++ b/lib/ftl/ftl_sb_common.h
@@ -33,13 +33,17 @@ struct ftl_superblock_gc_info {
 	uint64_t band_phys_id;
 	/* May be updating multiple fields at the same time, clearing/setting this marks the transaction */
 	uint64_t is_valid;
-};
+} __attribute__((packed));
+SPDK_STATIC_ASSERT(sizeof(struct ftl_superblock_gc_info) == 32,
+		   "ftl_superblock_gc_info incorrect size");
 
 struct ftl_superblock_header {
 	uint64_t magic;
 	uint64_t crc;
 	uint64_t version;
-};
+} __attribute__((packed));
+SPDK_STATIC_ASSERT(sizeof(struct ftl_superblock_header) == 24,
+		   "ftl_superblock_header incorrect size");
 
 struct ftl_superblock_md_region {
 	uint32_t		type;
@@ -47,7 +51,9 @@ struct ftl_superblock_md_region {
 	uint64_t		blk_offs;
 	uint64_t		blk_sz;
 	ftl_df_obj_id		df_next;
-};
+} __attribute__((packed));
+SPDK_STATIC_ASSERT(sizeof(struct ftl_superblock_md_region) == 32,
+		   "ftl_superblock_md_region incorrect size");
 
 struct ftl_superblock_shm {
 	/* SHM initialization completed */
diff --git a/lib/ftl/ftl_sb_current.h b/lib/ftl/ftl_sb_current.h
index b4ab2f656..4a8f233eb 100644
--- a/lib/ftl/ftl_sb_current.h
+++ b/lib/ftl/ftl_sb_current.h
@@ -32,12 +32,8 @@ struct ftl_superblock {
 	/* Maximum IO depth per band relocate */
 	uint64_t			max_reloc_qdepth;
 
-	/* Reserved fields */
-	uint64_t			reserved;
-
-	bool				reserved3;
-
-	uint32_t			reserved2;
+	/* Reserved field */
+	uint8_t				reserved3[16];
 
 	/* Last L2P checkpoint +1 (i.e. min_seq_id, 0:no ckpt) */
 	uint64_t			ckpt_seq_id;
@@ -45,7 +41,7 @@ struct ftl_superblock {
 	struct ftl_superblock_gc_info	gc_info;
 
 	struct ftl_superblock_md_region	md_layout_head;
-};
+} __attribute__((packed));
 
 SPDK_STATIC_ASSERT(offsetof(struct ftl_superblock, header) == 0,
 		   "Invalid placement of header");