I have dd crashing after running a few hours. Typically with a message likeInput/output error68424+1 records in68424+1 records out342124883968 bytes (342 GB) copied, 5114.68 s, 66.9 MB/sIs there something I can do about it?  Is there some way I can use the output?Or restart where it left off?Is there any reason to think it is because the partition being backed up is being used?It always crashes around 70-80%, often when the partition should be less-used.Since this process takes so long, it is difficult to try different things.I output to an image.  I could probably use a partition, but LVM is involved:sudo lvmdiskscan/dev/centos/swap [       3.89 GiB] /dev/sda1        [     500.00 MiB] /dev/centos/root [      50.00 GiB] /dev/sda2        [     465.27 GiB] LVM physical volume/dev/centos/home [     411.38 GiB] /dev/sdb1        [     931.51 GiB] 3 disks2 partitions0 LVM physical volume whole disks1 LVM physical volumedd conv=sync,noerror if=/dev/centos/home bs=2000000   of=/run/media/ob/X_1T_Media1GHD-PCTU3/c/sd9e22_cel.imagedd: error reading '/dev/centos/home': Input/output error171062+1 records in171063+0 records out342126000000 bytes (342 GB) copied, 4625.3 s, 74.0 MB/s220856+2 records in220858+0 records out441716000000 bytes (442 GB) copied, 6138.1 s, 72.0 MB/sFriday Morningddrescue --sector-size=2048 --cluster-size=$((256*512)) --sparse --verbose /dev/centos/home /run/media/ob/X_1T_Media1GHD-PCTU3/c/sd7c_dd.image /run/media/ob/X_1T_Media1GHD-PCTU3/c/sd7c_dd.mapGNU ddrescue 1.18.1About to copy 441714 MBytes from /dev/centos/home to /run/media/ob/X_1T_Media1GHD-PCTU3/c/sd7c_dd.image    Starting positions: infile = 0 B,  outfile = 0 B    Copy block size: 131072 sectors       Initial skip size: 32 sectorsSector size: 2048 BytesPress Ctrl-C to interruptrescued:   441714 MB,  errsize:    8192 B,  current rate:        0 B/s   ipos:   342124 MB,   errors:       1,    average rate:   60675 kB/s   opos:   342124 MB, run time:    2.02 h,  successful read:       9 s agoFinished But extundelete sd7c_dd.image  --restore-directory /home/ob/p -o /tmp/ttextundelete: Bad magic number in super-block when trying to open filesystem sd7c_dd.imageIf it helps,/dev/mapper/centos-home on /home type xfs (rw,relatime,attr2,inode64,noquota) 
dd crashing - what to do about it
dd;disk image