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   MSGID: 5529.linux@1:227/201 21bb7432   
   REPLY: 1:135/377 5d549a1e   
   PID: Synchronet 3.17c-Linux  Aug 15 2019 GCC 7.4.0   
   TID: SBBSecho 3.08-Linux r3.132 Aug 15 2019 GCC 7.4.0   
   CHRS: ASCII 1   
   -=> Rick Christian wrote to All <=-   
      
      
    RC>    Hello everybody!   
      
    RC> OK.. I've got a USB disk that worked fine.. then started to have some   
    RC> hissy fits.. wouldn't write during rsync ops...   
      
    RC> So for some reason it seems that it was getting hotter than normal,   
    RC> although its been sitting in that spot for the last 6months or so???   
   USB thumb drives, that get to hot ... can crush the onboard memory chips, and   
   controller.    
      
    RC> Anyway... tl;dr   
      
    RC> I put testdisk on a box... and it CAN FIND the partition that is there,   
    RC> that won't mount now... and it CAN SEE THE dirs in the partition so   
    RC> there is hope it might recover the data...   
      
    RC> BUT   
      
    RC> I'd like something that walks thru this step by step, that I can   
    RC> review, think on, review , think on review some more...   
      
    RC> I think I am just going to have Tarjay send me another 4TB drive and   
    RC> back up the original and then use this for a test to learn how to   
    RC> recover the partition and put back to use at least to read stuff....   
    RC> and possibly recover another drive that exhibits similar behavior. (Was   
    RC> stoped, unmounted, removed, and now wont remount..)   
      
    RC> So any one got some GOOD for RISK AVERSE persons tutorials, FAQ's etc..   
    RC> for testdisk?   
      
    RC> I looked at their site and it seems more geared to HD experts vs. I   
    RC> just want my stuff back (nothing critical) person.   
   Hi Rick,    
      
   If your drive was part of a lvm volume group, you may be missing the other part   
   of that volume that is preventing you from seeing all the data. IF not then   
   what I attempt to write below may help.    
      
   I'm not sure there is a recovery. USB ssd type drives (non-spinner drives),   
   have a write limit, eventually they just break.    
   Now I've not broke a internal or MR2 type ssd yet, but plenty of USB thumb   
   drives, and micro ssd drives, and often times this is earlier than expected end   
   of life so they are still under warranty.    
      
   If your computer is reporting a different size of the drive than manufacture   
   specification, you could have a controller issue, and that could be solved by a   
   controller swap. .. lots more steps for that recovery.   
      
   Here is what I usually do to test if the disk is broke, the easy way.    
      
   Caveat, must use linux, the drive wasn't part of an lvm volume group:   
      
   find the device of the disk. This is usually known when plugging it into the   
   computer, then do the following:   
      
   	dmesg |grep sd   
      
   Another easy way is to do the following:   
      
   	sudo fdisk -lu   
      
   Both will produce some identifier about your drive. If it doesn't you may have   
   another issue, but from your statements above those two command should work   
   well enough.   
      
   Next ... now understand this is where you must be precise in your command   
   syntax and typing.   
      
   NOTE!!! dd can wipe out all data on your drive if used incorrectly.    
   NOTE(2) dd can take a long long time to read a 4TB drive.    
      
   I'll explain what I'm doing and show you and example.    
   dd .. used to read the drive directly ignoring any partitions at all.    
   using dd I read the device from start to finish. If it can't read the entire   
   device it usually gets stuck or errors out, and this happens with USB ssd type   
   devices right at the memory chip boundaries. Lets say you have a 8 gig USB   
   thumb drive, most often I've seen at the 4GB boundary the drive is broke, or   
   the 2G boundary, ... etc.    
      
   from my command:   
      
   	dmesg |grep sd   
      
   I see a device [sdb] Attached SCSI removable disk ..   
   I use the dd command as follows:   
      
   	dd if=/dev/sdb of=/dev/null bs=512   
      
   eventually you'll get something like (i made up the numbers below):   
   	11118188+1 records in   
   	11118188+1 records out   
   	5000000000 bytes (5.7 GB, ... ) copied  ... 22 MB/s    
   If the size of 5.7 GB happens to be the size of your device, you probably have   
   a good working drive, if not, you have a broken ssd and recovery is very   
   difficult. Good working drives with ext2,3,4 formats can usually get data back   
   with an: fsck    
      
   dd will be attempting to read your drive device from start to finish. If it   
   finishes really early say after about 2GB when its a 8GB you see it, and it may   
   error out.   
      
   If you use the dd command as follows:   
      
   	dd if=/dev/sdb of=/dev/null bs=512 conv=noerror    
      
   and it runs for days and days, you've got it stuck on some spot that is broke   
   on your drive, but .. the last time I've ever used dd on a USB thumb drive,   
   I've never seen this, I've only seen it stop reading prior to reading the   
   entire drive.    
      
   If your dd can read the entire device, then you can used fsck on the drive, and   
   there are many options.    
   Also if dd can read the entire device, I usually use dd to make an exact   
   duplicate of my drive, and operate on the image.    
      
   	dd if=/dev/sdb of=./sdb.drive.img bs=512 conv=noerror,notrunc    
      
   Then I start operating on the image. If this is an lvm type setup, ... way more   
   things to do,   
      
      
   For spinner drives .. there is a different process, you can use dd, but other   
   methods work depending on the partitions and format type.    
      
   	   
       
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