![]() Its simpler and more idiot proof in my opinion. I also personally favour the gnuddrescue syntax. It also would do an image of a drive that's perfectly healthy. It gives you the best chance of recovering data but at the cost of possibly more time, and the optimisation being for maximum data recovery over perfectness. It drives in nails and it takes them out. You MIGHT be able to get out nails with a specialised tool, but not with your generic hammer. Gnu dd rescue is a specialised tool that happens to do the same thing the generic one does. ddrescue also should give you a bit-perfect copy you can verify with a checksum. And at the very least it looks something like this, and any other hammer you find does at least what this does. Its a bit of steel on a stick, you know every workshop has one, and it bashes in nails fine. However you can walk to any linux system and do an image. There's no built in verification, there's no check summing, there's no fancy bits. Its designed around being minimal and simple. Luckly, on my case, a big database 4gb file was only affected.Quite simply? DD is a standard tool which you will predictably find in some shape or form in most unix or unix inspired OS. If your blocks are all over the disk, several files could be affected. About 4 blocks at a time together in groups where detected bad. NOTE: My bad blocks where pretty much close to each other. I hope this will be usefull for others trying to backup faulty drives. ![]() No corruption at all, it just does not copy the faulty blocks and fills it with empty NULs.Īfter the copy with DD was done, I just replace that bad file reverting Filezilla from a past backup and everything worked OK. What the ‘conv=noerror,sync’ does, is to pad out bad reads with NULs, while ‘iflag=fullblock’ caters for short reads, but keeps in sync your data up to the end. ![]() The amount of times made a noise, was because it found another bad block and tells you about on display error msg. It does copy block by block, and thru all my bad blocks made the same noise. Each bad block encountered sound like a banging on the faulty drive. dd if=/dev/sdb of=/dev/sda bs=512 conv=noerror,sync iflag=fullblock So I then use the parameters as explained on the page search the "For failing disks" part. My block size is 512 so I use that default number to run DDģrd each block is 512 size, so what I done is to set bs=512Įach time I runned DD regularly as I always do, my data, after the errors, will come out corrupted. If no bad blocks are found, then your drive blocks are OK and need to figure something else out. To duplicate the disk, then I had to find the bad blocks on the disk using this procedure:ġst find out the problem disk identifying the HD info using fdisk -lĢnd if lets say your disk is /dev/sdb then you need to run the commandīadblocks -v /dev/sdb it will list all you bad blocks on the drive. Luckly I have a previous backup of same file. I notice that one big file was not copying correctly (Stopping in the middle and restarting the transfer). The first thing I have done is backup files using regular Filezilla to backup all good data. I was having problems duplicating (backing up a disk) with about 30 bad blocks. With bad blocks I have just recovered this morning, took me twice the time. It usually takes me 20 min to backup using DD a 1 tera healthy hd. Setting it to 0 disables TLER): # smartctl -l scterc,50,50 /dev/sdaĭepends on the size of your hard drive and how many bad blocks it has. To set it to a fixed value (5.0 seconds in this example. To check the current setting ("disabled" means an unlimited time, which you do not want): # smartctl -l scterc /dev/sda Linux has a tool called smartctl (in the smartmontools package). This approach can be combined with using ddrescue, of course. Not all HDDs have it, but you can use it to limit the time on the HDD controller itself. In case the HDD itself is taking too long, you can try to enable a feature called TLER ( Time Limited Error Recovery) or CCTL ( Command Completion Time Limit). Here are some additional sources to using ddrescue: Run, you must specify a non-zero number of retry passes. To retry bad sectors detected on a previous Trying to rescue the most difficult parts of the file.Įxit after given number of retry passes. # ddrescue -r1 /dev/sda /dev/sdb rescue.logįrom the ddrescue info-page: -n, -no-scrape If you later feel like doing more retries, you can use the same logfile to run ddrescue again with different options (like more retries) and it will retry only the necessary blocks.Įxample usage: # ddrescue -n /dev/sda /dev/sdb rescue.log It can also use a logfile, so it records which blocks were bad. First, for the software to use: you could try using ddrescue instead of dd.ĭdrescue has a switch to do only a limited number of retries.
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