Hi, On 19-07-12 16:55, Sébastien Han wrote:
Hi Cephers! I'm working with rbd mapping. I figured out that the block device size of the rbd device is not update while the device is mounted. Here my tests:
iirc this is not something RBD specific, but since the device is in use it can't be re-read by the kernel.
So when you unmount it the kernel can re-read the header and resize the device.
Wido
1. Pick up a device and check his size # rbd ls size # rbd info test rbd image 'test': size 10000 MB in 2500 objects order 22 (4096 KB objects) block_name_prefix: rb.0.6 parent: (pool -1) 2. Map the device # rbd map --secret /etc/ceph/secret test # rbd showmapped id pool image snap device 1 rbd test - /dev/rbd1 3. Put a fs on it and check the block device size # mkfs.ext4 /dev/rdb1 ... ... # fdisk -l /dev/rbd1 Disk /dev/rbd1: 10.5 GB, 10485760000 bytes 4. Mount it # mount /dev/rbd1 /mnt # df -h /dev/rbd1 9.8G 277M 9.0G 3% /mnt 5. Change the image size # rbd resize --size 11000 test Resizing image: 100% complete...done. # rbd info test rbd image 'test': size 11000 MB in 2750 objects order 22 (4096 KB objects) block_name_prefix: rb.0.6 parent: (pool -1) At this point of time, if you perform the fdisk -l /dev/rbd1, the block device size will remain the same. 6. Unmount the device: # umount /media # fdisk -l /dev/rbd1 Disk /dev/rbd1: 11.5 GB, 11534336000 bytes Unmounting the directory did update the block device size. Of course you can do something really fast like: # umount /media && mount /dev/rbd1 /media That will work, it's a valid solution as long as there is no opened file. I won't use this trick in production... I also tried to "mount -o remount" and it didn't work. 7. Resize the fs (this can be performed while the fs is mounted): # e2fsck -f /dev/rbd1 e2fsck 1.42 (29-Nov-2011) Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information /dev/rbd1: 11/644640 files (0.0% non-contiguous), 77173/2560000 blocks # resize2fs /dev/rbd1 resize2fs 1.42 (29-Nov-2011) Resizing the filesystem on /dev/rbd1 to 2816000 (4k) blocks. The filesystem on /dev/rbd1 is now 2816000 blocks long. Did I miss something? Is this feature coming? Thank you in advance :) -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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