root@u18:~# rbd create kvm/test002.img --size 20
root@u18:~# rbd info kvm/test002.img
rbd image 'test002.img':
size 20480 kB in 5 objects
order 22 (4096 kB objects)
block_name_prefix: rb.0.2f13.2ae8944a
format: 1
root@u18:~# rbd map kvm/test002.img
root@u18:~# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 298.1G 0 disk
├─sda1 8:1 0 296.2G 0 part /
├─sda2 8:2 0 1K 0 part
└─sda5 8:5 0 1.9G 0 part [SWAP]
sdb 8:16 0 465.8G 0 disk
├─sdb1 8:17 0 200G 0 part /ceph_node0
├─sdb2 8:18 0 1K 0 part
├─sdb5 8:21 0 100G 0 part
└─sdb6 8:22 0 165.8G 0 part /data2
rbd0 250:0 0 40G 0 disk
rbd1 250:16 0 20M 0 disk
zram0 251:0 0 936.4M 0 disk [SWAP]
root@u18:~# mkfs.ext4 /dev/rbd1
mke2fs 1.42 (29-Nov-2011)
Filesystem label=
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
Stride=4096 blocks, Stripe width=4096 blocks
5136 inodes, 20480 blocks
1024 blocks (5.00%) reserved for the super user
First data block=1
Maximum filesystem blocks=20971520
3 block groups
8192 blocks per group, 8192 fragments per group
1712 inodes per group
Superblock backups stored on blocks:
8193
Allocating group tables: done
Writing inode tables: done
Creating journal (1024 blocks): done
Writing superblocks and filesystem accounting information: done
root@u18:~# mount /dev/rbd1 /mnt
root@u18:~# echo test > /mnt/a.log
root@u18:~# vim a.log
root@u18:~# vim /mnt/a.log
root@u18:~# umount /mnt
root@u18:~# rbd unmap /dev/rbd1
root@u18:~# rbd resize --size 40960 kvm/test002.img
Resizing image: 100% complete...done.
root@u18:~# rbd info kvm/test002.img
rbd image 'test002.img':
size 40960 MB in 10240 objects
order 22 (4096 kB objects)
block_name_prefix: rb.0.2f13.2ae8944a
format: 1
root@u18:~# rbd info kvm/test002.img
rbd image 'test002.img':
size 40960 MB in 10240 objects
order 22 (4096 kB objects)
block_name_prefix: rb.0.2f13.2ae8944a
format: 1
root@u18:~# rbd map kvm/test002.img
root@u18:~# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 298.1G 0 disk
├─sda1 8:1 0 296.2G 0 part /
├─sda2 8:2 0 1K 0 part
└─sda5 8:5 0 1.9G 0 part [SWAP]
sdb 8:16 0 465.8G 0 disk
├─sdb1 8:17 0 200G 0 part /ceph_node0
├─sdb2 8:18 0 1K 0 part
├─sdb5 8:21 0 100G 0 part
└─sdb6 8:22 0 165.8G 0 part /data2
rbd0 250:0 0 40G 0 disk
rbd1 250:16 0 40G 0 disk
zram0 251:0 0 936.4M 0 disk [SWAP]
root@u18:~# rbd unmap /dev/rbd1
root@u18:~# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 298.1G 0 disk
├─sda1 8:1 0 296.2G 0 part /
├─sda2 8:2 0 1K 0 part
└─sda5 8:5 0 1.9G 0 part [SWAP]
sdb 8:16 0 465.8G 0 disk
├─sdb1 8:17 0 200G 0 part /ceph_node0
├─sdb2 8:18 0 1K 0 part
├─sdb5 8:21 0 100G 0 part
└─sdb6 8:22 0 165.8G 0 part /data2
rbd0 250:0 0 40G 0 disk
zram0 251:0 0 936.4M 0 disk [SWAP]
root@u18:~# rbd map kvm/test002.img
root@u18:~# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 298.1G 0 disk
├─sda1 8:1 0 296.2G 0 part /
├─sda2 8:2 0 1K 0 part
└─sda5 8:5 0 1.9G 0 part [SWAP]
sdb 8:16 0 465.8G 0 disk
├─sdb1 8:17 0 200G 0 part /ceph_node0
├─sdb2 8:18 0 1K 0 part
├─sdb5 8:21 0 100G 0 part
└─sdb6 8:22 0 165.8G 0 part /data2
rbd0 250:0 0 40G 0 disk
rbd1 250:16 0 40G 0 disk
zram0 251:0 0 936.4M 0 disk [SWAP]
root@u18:~# mount /dev/rbd1 /mnt
root@u18:~# parted /dev/rbd1 print free
root@u18:~# parted /dev/rbd1 print free
Model: Unknown (unknown)
Disk /dev/rbd1: 42.9GB
Sector size (logical/physical): 512B/512B
Partition Table: loop
Number Start End Size File system Flags
1 0.00B 42.9GB 42.9GB ext4
root@u18:~# vim /mnt/a.log
root@u18:~# cat /mnt/a.log
test