diff --git a/mk/disks-and-filesystems.mk b/mk/disks-and-filesystems.mk
new file mode 100644
index 0000000..d1d8a42
--- /dev/null
+++ b/mk/disks-and-filesystems.mk
@@ -0,0 +1,72 @@
+ZRAMDIR ?= /tmp/zram
+
+# Currently not working with alpine linux.
+zram: zram-mkdir zram-module zram-create zram-format zram-mount
+unzram: zram-umount zram-free
+
+btrzram: zram-mkdir zram-module zram-create btrzram-format zram-mount
+
+zram-mkdir:; -mkdir $(ZRAMDIR) 2>/dev/null
+
+zram-module:; modprobe zram
+zram-create:; zramctl --find --size 50000M -a zstd
+
+# -b 2048    block size, cannot be used (mkfs.ext4 wants 4k blocks minimum)
+# -N xxx     nb of inodes
+# -i xxx     higher inode ratio
+zram-format:; mkfs.ext4 -N 50000000 /dev/zram0
+zram-mount:; mount /dev/zram0 $(ZRAMDIR)
+
+zram-umount:; -umount $(ZRAMDIR)
+zram-free:; -zramctl -r /dev/zram0
+
+### BTRFS
+
+BTRFS_DIR ?= /tmp/btrfs
+BTRFS_IMG ?= /tmp/btrfs.img
+BTRFS_SIZ ?= 5000
+BTRFS_SECTOR_SIZE ?= 4096
+BTRFS_NODE_SIZE ?= 4096  # Minimal accepted value.
+BTRFS_LOOP ?= /dev/loop100
+BTRFS_COMP ?= zstd:8
+
+# apt install btrfs-progs
+btrfs: btrfs-mkdir btrfs-create btrfs-loop btrfs-format btrfs-mount btrfs-chown
+btrfs-mkdir:; [ ! -d $(BTRFS_DIR) ] && mkdir $(BTRFS_DIR) 2>/dev/null || :
+btrfs-create:
+	[ ! -f $(BTRFS_IMG) ] && su karchnu -c "dd if=/dev/zero of=$(BTRFS_IMG) bs=1M count=$(BTRFS_SIZ)" || :
+btrfs-loop:; losetup --sector-size $(BTRFS_SECTOR_SIZE) $(BTRFS_LOOP) $(BTRFS_IMG)
+btrfs-format:; mkfs.btrfs -s $(BTRFS_SECTOR_SIZE) -n $(BTRFS_NODE_SIZE) -L BTRDATA $(BTRFS_LOOP)
+btrfs-mount:; mount -o compress=$(BTRFS_COMP) $(BTRFS_LOOP) $(BTRFS_DIR)
+btrfs-chown:; chown karchnu $(BTRFS_DIR)
+
+unbtrfs: btrfs-umount btrfs-unloop btrfs-rm
+btrfs-unloop:; [ -b $(BTRFS_LOOP) ] && losetup -d $(BTRFS_LOOP) || :
+btrfs-umount:; umount $(BTRFS_DIR)
+btrfs-rm:; rm $(BTRFS_IMG)
+
+### EXT4
+
+EXT4_DIR ?= /tmp/ext4
+EXT4_IMG ?= /tmp/ext4.img
+EXT4_SIZ ?= 5000
+EXT4_SECTOR_SIZE ?= 1024
+EXT4_INODE_NUMBER ?= 10000000
+#EXT4_SECTOR_SIZE ?= 4096
+#EXT4_INODE_NUMBER ?= 1500000
+EXT4_INODE_SIZE ?= 256
+EXT4_LOOP ?= /dev/loop1000
+
+ext4: ext4-mkdir ext4-create ext4-loop ext4-format ext4-mount ext4-chown
+ext4-mkdir:; [ ! -d $(EXT4_DIR) ] && mkdir $(EXT4_DIR) 2>/dev/null || :
+ext4-create:
+	[ ! -f $(EXT4_IMG) ] && su karchnu -c "dd if=/dev/zero of=$(EXT4_IMG) bs=1M count=$(EXT4_SIZ)" || :
+ext4-loop:; losetup --sector-size $(EXT4_SECTOR_SIZE) $(EXT4_LOOP) $(EXT4_IMG)
+ext4-format:; mkfs.ext4 -b $(EXT4_SECTOR_SIZE) -I $(EXT4_INODE_SIZE) -N $(EXT4_INODE_NUMBER) -L EXT4DATA $(EXT4_LOOP)
+ext4-mount:; mount $(EXT4_LOOP) $(EXT4_DIR)
+ext4-chown:; chown karchnu $(EXT4_DIR)
+
+unext4: ext4-umount ext4-unloop ext4-rm
+ext4-unloop:; [ -b $(EXT4_LOOP) ] && losetup -d $(EXT4_LOOP) || :
+ext4-umount:; umount $(EXT4_DIR) || :
+ext4-rm:; rm $(EXT4_IMG) || :