5TB exfat

Using TestDisk to repair the filesystem
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cloaked1
Posts: 5
Joined: 05 Jun 2017, 18:47

5TB exfat

#1 Post by cloaked1 »

I'm not sure why this happened, but I know what I did and now I'm trying to recover from it. Perhaps you wouldn't mind assisting:

I have a 5TB external zero-partition drive formatted to exfat in Linux (mke2fs.exfat /dev/sdb) which worked fine under Linux on macbook running Ubuntu 14.04. A few weeks ago, I umounted the volume from the laptop and disconnected it. I brought it home and plugged it in and it no worky.

I've been using testdisk to do a deep-search on it. The go-'round it went for about eight days and got to 70-ish%, but something happened and the deep-search just stopped (like the light on the drive turned off and everything. No idea what happened). I rebooted the laptop and started the deep-search again. I'm in the seventh day (approximate) and am getting the exact same results (promising) so far. I posted a question about this in https://superuser.com/questions/1210995 ... ge-results on the first go-'round. Here are my current results (unfinished).

TestDisk 7.1-WIP, Data Recovery Utility, April 2017
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org
Disk /dev/sdb - 5000 GB / 4657 GiB - CHS 608001 255 63
Analyse cylinder 382193/608000: 62%
MS Data 2431873279 2431888310 15032 [Compressed]
MS Data 1 2431893759 2431897566 3808 [Compressed]
MS Data 2431906047 2431921990 15944 [Compressed]
MS Data 2431926527 2431930518 3992 [Compressed]
MS Data 2434177535 2434192566 15032 [Compressed]
MS Data 2434198015 2434201822 3808 [Compressed]
MS Data 2434210303 2434226246 15944 [Compressed]
MS Data 2434230783 2434234774 3992 [Compressed]
Mac HFS 2436697600 2843726335 407028736
check_FAT: Unusual media descriptor (0xf8!=0xf0)
Warning: number of heads/cylinder mismatches 64 (FAT) != 255 (HD)
Warning: number of sectors per track mismatches 32 (FAT) != 63 (HD)
EFI System 3167044620 3167049291 4672 [EFI System Partition] [NO NAME]
Unknown 3355538484 15781843504821299 15781840149282816 [~IM-vM-?b~BV^C )M-u~MM-5a^U&4^B`,~S|b~SM-4 M-)|^ MS Data 3416839383 3500232734 83393352 [/]
Unknown 3514647080 4947095670 1432448591 MS Data 3569660631 3653053982 83393352 [/]
MS Data 3778724465 3782918768 4194304
MS Data 3782918768 3787113071 4194304
MS Data 3778724465 3782918768 4194304
]]

Given the current state, is there anything I can do to recover this filesystem/partition?

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cgrenier
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Joined: 18 Feb 2012, 15:08
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Re: 5TB exfat

#2 Post by cgrenier »

As there was no partition, it's useless to search for a partition.
Run TestDisk, select /dev/sdb, partition type: None, Advanced, List. What is the result ? Same question for the Boot menu.

cloaked1
Posts: 5
Joined: 05 Jun 2017, 18:47

Re: 5TB exfat

#3 Post by cloaked1 »

I get a list of my files all nice and pretty when I go with None, Advanced, List. For boot, I get

TestDisk 7.1-WIP, Data Recovery Utility, April 2017
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org

Disk /dev/sdb - 5000 GB / 4657 GiB - CHS 608001 255 63
Partition Start End Size in sectors
P exFAT 0 0 1 608001 80 62 9767541167

Boot sector
exFAT OK

Backup boot record
Bad

Sectors are not identical.

cloaked1
Posts: 5
Joined: 05 Jun 2017, 18:47

Re: 5TB exfat

#4 Post by cloaked1 »

For the boot issue where the backup boot sector did not match the boot sector, I chose to copy the bootsector over the backup and now they are identical.

I misspoke a little. So as I mentioned, I get a list of my files. I decided to drill down into the directories and I found two where testdisk was unable to drill down giving the error that the filesystem might be damaged:

TestDisk 7.1-WIP, Data Recovery Utility, April 2017
Christophe GRENIER <grenier@cgsecurity.org>
http://www.cgsecurity.org
P exFAT 0 0 1 608001 80 62 9767541167
Directory /backup/files

No file found, filesystem may be damaged.


I don't suppose there's a way to fix that is there? The windows machine still doesn't recognize the disk when it's plugged in so there's no way of which I'm aware to chkdsk it.

Window's disk manager thinks this disk has 5 partitions (three healthy "primary partition", and two unallocated), which makes no sense to me.

cloaked1
Posts: 5
Joined: 05 Jun 2017, 18:47

Re: 5TB exfat

#5 Post by cloaked1 »

I purchased another 5TB drive and am currently running an image creation from the broken filesystem to the new disk. Once that is done, I'm going to attempt to fix the broken filesystem...just not sure how to do that part yet. I attempted to chkdsk the raw volume, but windows isn't reporting it at all it seems. Some help there would be greatly appreciated if you have any ideas. The commands I tried were:

[via Admin cmd window]
C:\> mountvol
...
Possible values for VolumeName along with current mount points are:

\\?\Volume{7b51dfff-3cb3-11e5-a75e-806e6f6e6963}\
*** NO MOUNT POINTS ***

\\?\Volume{a95147c9-289e-408b-90f5-63f959dcb5f4}\
F:\

\\?\Volume{7b51e000-3cb3-11e5-a75e-806e6f6e6963}\
C:\

\\?\Volume{7b51e001-3cb3-11e5-a75e-806e6f6e6963}\
D:\

\\?\Volume{7b51e002-3cb3-11e5-a75e-806e6f6e6963}\
*** NO MOUNT POINTS ***

\\?\Volume{489b372e-312c-11e7-af86-806e6f6e6963}\
E:\

Now thinking that one of the volumes with no mount points might be the right one, I tried:

C:\> chkdsk /f "\\?\Volume{7b51e002-3cb3-11e5-a75e-806e6f6e6963}"

The problem is that neither of the two volumes in the list above were the 5TB USB volume I need to check. Not sure what that's about yet.

cloaked1
Posts: 5
Joined: 05 Jun 2017, 18:47

Re: 5TB exfat

#6 Post by cloaked1 »

crickets?

Just curious if you're aware of a way to fix the exfat FS that's corrupt and it doesn't show up as a volume in windows and Linux tools fail to fix the issue with a VBR error (let me know if you'd like to see the actual error). Truly frustrating.

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