Very Slow Advanced Scan

How to use TestDisk to recover lost partition
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Posts: 4
Joined: 19 Mar 2015, 01:31

Very Slow Advanced Scan

#1 Post by johnywhy »


I have a hard disk that recently went bad. Running quick scan runs quickly, but the advanced scan is taking so long it looks like it will take about 2 months to scan the whole drive.

I'm thinking the scanner is RETRYING multiple times, or has a long timeout value. Clearly, the cylinders are bad, and there's no advantage to constantly retrying.

Is there a way to change the number of times the scanner tries, or change the timeout value?


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Re: Very Slow Advanced Scan

#2 Post by cgrenier »

Try to clone the disk to a new empty disk using gnu ddrescue
Once the copy is done, remove the original disk and try TestDisk again on the clone.

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Re: Very Slow Advanced Scan

#3 Post by johnywhy »

But, can i clone a disk that cannot be mounted?
or, how can i image a partition that cannot be mounted?

ddrescue doc says "only mountable device formats can be rescued with ddrescue."

gparted can see it, but cannot mount. see attached pictures.

however, when i ran thee following command, ddrescue DID begin to image the entire drive. Is this process doomed to fail, since the partitions cannot be mounted?

Code: Select all

ddrescue -d /dev/sda /mnt/sdc1/ddrescue/asus3-21.img /mnt/sdc1/ddrescue/asus3-21.log
attached pic shows this process happening in terminal window.
gparted2.png (41.15 KiB) Viewed 1753 times
gparted3.png (49.48 KiB) Viewed 1753 times
ddrescue.png (22.33 KiB) Viewed 1752 times

Posts: 4
Joined: 19 Mar 2015, 01:31

Re: Very Slow Advanced Scan

#4 Post by johnywhy »

seems to be working, but taking forever. i only need to recover that one partition, not the whole drive.

can i use the "First Sector" value as-is for the ddrescue -i option? Or do i need to divide by 8 or 512 or something?