On Tuesday, 18 December 2018 18:51:55 GMT Grant Taylor wrote: > On 12/18/2018 10:42 AM, Mick wrote: > > I know others have commented on the reliability of recovering data from > > drives connected via USB caddy, but I have had satisfactory results on a > > number of cases. > > I think it completely depends on the type of problem. In my experience, > SATA-to-USB adapters don't deal well with physical hard drive / media > errors. (At least compared to SATA connections on the motherboard.) I > think their retry mechanisms are somewhat limited. Conversely, software > / file system / logical corruption issues are likely perfectly fine over > USB.
I ran ddrescue while the drive was still on the laptop. The clone was on the USB caddy. > > I cloned the whole drive having run ddrescue backwards and forwards a > > couple of times. c/f/gdisk would see all partitions, but when I tried to > > mount the cloned /dev/sdb4 (NTFS) with ntfs-3g it complained there was no > > device found (/dev/sdb4). I got the same error with the failing drive. > > Seeing the partitions in the partition table is independent of the > device file being there. - Did the device file exist? - I > occasionally have to run (k)part(x) to tell the kernel that the > partition is there and to create the device file. The disk block device is there and so is the first partition (only): ls -la /dev/sdb* brw-rw---- 1 root disk 8, 16 Dec 19 11:20 /dev/sdb brw-rw---- 1 root disk 8, 17 Dec 19 11:20 /dev/sdb1 However, there's 6 partitions in total: Disk /dev/sdb: 1953525168 sectors, 931.5 GiB Model: LucidPort USB300 Sector size (logical/physical): 512/512 bytes Disk identifier (GUID): 1A95F5D1-5630-4E06-9DC3-36841C786DDF Partition table holds up to 128 entries Main partition table begins at sector 2 and ends at sector 33 First usable sector is 34, last usable sector is 1953525134 Partitions will be aligned on 2048-sector boundaries Total free space is 4770 sectors (2.3 MiB) Number Start (sector) End (sector) Size Code Name 1 2048 821247 400.0 MiB 2700 Basic data partition 2 821248 1353727 260.0 MiB EF00 EFI system partition 3 1353728 1615871 128.0 MiB 0C01 Microsoft reserved ... 4 1615872 1911737034 910.8 GiB 0700 Basic data partition 5 1911738368 1915412479 1.8 GiB 2700 6 1915412480 1953523711 18.2 GiB 0700 Basic data partition I can see partition 4 I was trying to recover, but could not add it: partx --show --nr 4 /dev/sdb NR START END SECTORS SIZE NAME UUID 4 1615872 1911737034 1910121163 910.8G Basic data partition fea85fb3- cfdb-4868-a1ad-bab264dad237 partx --add --nr 4 /dev/sdb partx: /dev/sdb: error adding partition 4 partx --add /dev/sdb partx: /dev/sdb: error adding partitions 1-6 In any case, losetup with offset/size succeeded in mounting it and I was able to access the fs on it. -- Regards, Mick
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