My way: Half throttle
As with all suggestions here: DISCLAIMER: DO THAT AT YOUR OWN RISK.
I got an unhappy Western Digital "Eco" Drive wd10ezrx harddrive which I am recovering at the moment. It was clicking since yesterday and today I tried to access some of files which took quite some time. And the clicking got even louder (or was it just me?). Well, I downloaded Knoppix and started to run ddrescue on that drive which does do its job quite well:
I see valid data in the binary output. The MFT of the NTFS volume is there, everything is going to be alright. But after some time, the speed got slower and slower, extremely slow, until 32kb/sec etc. I tried all settings from the internet, from many forums. And I noticed that it's getting slower and slower when I have the recovery process running long time. It was quite strange that from time to time, it speeded up a little bit, but just for some seconds.
Now I read a lot about freezing which is an interesting idea and which also seems to work a lot. I also punched the drive and every time the head loses control the drive stops and starts again - but with full speed!
So I tried the following: I used
hdparm -Y /dev/sdX
regularly to stop the drive. It fires up again automatically for sure (because he wants to read) and then it starts to copy in good speed for some seconds - until it starts to click and copy with like 32kb/sec again. Arg! And again I noticed he starts to click after some time of copying. The heads seems to hit something after some time - whatever it is and for whatever reason, so I got an idea...
My next idea was to stop (-Y) and start/standby (-y) the drive regularly, like
while [ 1 ]; do hdparm -Y /dev/sdX; hdparm -y /dev/sdX; sleep 30; done
I played with some sleeping values and after some time I got very good values, which are
while [ 1 ]; do hdparm -Y /dev/sdX; sleep 5; hdparm -y /dev/sdX; sleep 10; done
Now, the drive can't start to click because this just happens after some time - for whatever reason. I stop the harddrive again before he starts to do this, otherwise he hangs up while reading the sectors.
I copied 20GB in 10 minutes now. I'm quite glad that works and I hope my harddisk survives this process.