# rbd info foo rbd image 'foo': size 10240 MB in 2560 objects order 22 (4096 KB objects) block_name_prefix: rb.0.10a6.74b0dc51 format: 1 # fdisk -l /dev/rbd0 Disk /dev/rbd0: 10.7 GB, 10737418240 bytes 255 heads, 63 sectors/track, 1305 cylinders, total 20971520 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 4194304 bytes / 4194304 bytes Disk identifier: 0x00000000 Disk /dev/rbd0 doesn't contain a valid partition table # mkfs.ext3 /dev/rbd0 mke2fs 1.42 (29-Nov-2011) Filesystem label= OS type: Linux Block size=4096 (log=2) Fragment size=4096 (log=2) Stride=1024 blocks, Stripe width=1024 blocks 655360 inodes, 2621440 blocks 131072 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=2684354560 80 block groups 32768 blocks per group, 32768 fragments per group 8192 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632 Allocating group tables: done Writing inode tables: done Creating journal (32768 blocks): done Writing superblocks and filesystem accounting information: done # mount -t ext3 /dev/rbd0 /mnt # df -h /mnt Filesystem Size Used Avail Use% Mounted on /dev/rbd0 9.9G 151M 9.2G 2% /mnt # fdisk -l /dev/rbd0 Disk /dev/rbd0: 10.7 GB, 10737418240 bytes 255 heads, 63 sectors/track, 1305 cylinders, total 20971520 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 4194304 bytes / 4194304 bytes Disk identifier: 0x00000000 Disk /dev/rbd0 doesn't contain a valid partition table # rbd resize foo --size 20480 Resizing image: 100% complete...done. # echo "now i'm expecting 20 GB block device and 10 GB file system # fdisk -l /dev/rbd0 Disk /dev/rbd0: 10.7 GB, 10737418240 bytes 255 heads, 63 sectors/track, 1305 cylinders, total 20971520 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 4194304 bytes / 4194304 bytes Disk identifier: 0x00000000 Disk /dev/rbd0 doesn't contain a valid partition table # echo "unmounting increasing rbd idevice" # umount /mnt # fdisk -l /dev/rbd0 Disk /dev/rbd0: 21.5 GB, 21474836480 bytes 255 heads, 63 sectors/track, 2610 cylinders, total 41943040 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 4194304 bytes / 4194304 bytes Disk identifier: 0x00000000 Disk /dev/rbd0 doesn't contain a valid partition table