Description of problem: I am trying to copy /root, /home from a single disk (running the os) to a bigger raid 1 disk pair running in the same chassis.
fedora is the lvm vg_group of the running system, fedora23 is the lvm vg_group of the new disks (raid 1, 2TB disks). [root@hoho8-chidig-com user1]# lvscan ACTIVE '/dev/fedora/swap' [15.57 GiB] inherit ACTIVE '/dev/fedora/home' [865.45 GiB] inherit ACTIVE '/dev/fedora/root' [50.00 GiB] inherit ACTIVE '/dev/fedora23/swap' [15.60 GiB] inherit ACTIVE '/dev/fedora23/root' [50.00 GiB] inherit ACTIVE '/dev/fedora23/home' [1.75 TiB] inherit Below is the command I'm using to copy over one partition to the raid pair: [root@hoho8-chidig-com user1]# dd if=/dev/fedora/root of=/dev/fedora23/root 104857600+0 records in 104857600+0 records out 53687091200 bytes (54 GB) copied, 5639.3 s, 9.5 MB/s [root@hoho8-chidig-com user1]# [root@hoho8-chidig-com user1]# df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 16G 0 16G 0% /dev tmpfs 16G 392K 16G 1% /dev/shm tmpfs 16G 1.8M 16G 1% /run tmpfs 16G 0 16G 0% /sys/fs/cgroup /dev/mapper/fedora-root 50G 27G 20G 58% / tmpfs 16G 84K 16G 1% /tmp /dev/loop0 1.9G 3.0M 1.7G 1% /srv/node/swift_loopback /dev/mapper/fedora-home 852G 57G 752G 7% /home /dev/sdc1 477M 215M 233M 48% /boot tmpfs 3.2G 8.0K 3.2G 1% /run/user/42 tmpfs 3.2G 24K 3.2G 1% /run/user/1000 Note that dd says 54GB were copied over into a disk partition of size only 50GB. No errors during the copy. And the results show that only 27G was in the fedora partition to start with. (54GB is double 27GB - this may be a clue) Another example: [root@hoho8-chidig-com user1]# dd if=/dev/fedora/home of=/dev/fedora23/home 1814978560+0 records in 1814978560+0 records out 929269022720 bytes (929 GB) copied, 32437.8 s, 28.6 MB/s [root@hoho8-chidig-com user1]# Taking a look at the data size on the target partitions: [root@hoho8-chidig-com user1]# mount /dev/fedora23/root /mnt/rootn [root@hoho8-chidig-com user1]# mount /dev/fedora23/home /mnt/homen [root@hoho8-chidig-com user1]# du -h /mnt/rootn | tail -1 26G /mnt/rootn [root@hoho8-chidig-com user1]# du -h /mnt/homen | tail -1 57G /mnt/homen for the rootn partition, the 26G copied size is consistent with the source size. For the homen partition, the 57G is consistent with the source size. However, the count given by the dd copies don't match: In the case of the root->rootn copy it is 54G instead of 27G in the case of the home->homen copy it is 942G instead of 57G Version-Release number of selected component (if applicable): dd is (coreutils) 8.24 How reproducible: I did two tests - as shown Steps to Reproduce: 1. create raid 1 pair 2. copy a 3rd single disk partition to a raid1 pair lvm partition 3. do df and compare results. Actual results: As shown above in problem narative. Expected results: I would think that the sizes reported by dd and df would be comparable, but they are not. Additional info: See also https://bugzilla.redhat.com/show_bug.cgi?id=1303456