Page 1 of 5

HDDSuperClone vs ddrescue

Posted: Thu Mar 30, 2017 8:53 am
by jol
I have made some tests lately, and checked the results of HDDSuperClone vs ddrescue against: SAS, SATA, USB HDDs, micro SD and flash drives, some of them in good working condition some of them problematic

Conclusion: HDDSuperClone's speed of cloning is slower then ddrescue, but the good part is.... that its giving much better results than ddrescue

@maximus, Keep up the great work

HDDSuperClone vs ddrescue

Posted: Sun Apr 02, 2017 1:48 am
by Amarbir[CDR-Labs]
jol wrote:I have made some tests lately, and checked the results of HDDSuperClone vs ddrescue against: SAS, SATA, USB HDDs, micro SD and flash drives, some of them in good working condition some of them problematic

Conclusion: HDDSuperClone's speed of cloning is slower then ddrescue, but the good part is.... that its giving much better results than ddrescue

@maximus, Keep up the great work



@ Jol,
As The project is based on dd rescue itself why should it be slow ,This is interesting ,Is this due to the fact he has implemented many fancy things into it or what

HDDSuperClone vs ddrescue

Posted: Sun Apr 02, 2017 9:11 am
by Jared
It's not exactly based on ddrescue. It is using it's own imaging algorithms completely. The guy who's making it is someone who helped to develop the algorithm that ddrescue actually used.

I'm not surprised it's a bit slower, the program is more advanced and takes more control of the IO to the drive than ddrescue does. That overhead is bound to make it somewhat slower, but it's still quite fast.

HDDSuperClone vs ddrescue

Posted: Sun Apr 02, 2017 9:20 am
by Amarbir[CDR-Labs]
Jared wrote:It's not exactly based on ddrescue. It is using it's own imaging algorithms completely. The guy who's making it is someone who helped to develop the algorithm that ddrescue actually used.

I'm not surprised it's a bit slower, the program is more advanced and takes more control of the IO to the drive than ddrescue does. That overhead is bound to make it somewhat slower, but it's still quite fast.


Jared ,
Thats a Fair Explanation

HDDSuperClone vs ddrescue

Posted: Sun Apr 02, 2017 7:18 pm
by jol
Jared wrote:but it's still quite fast.

That's right, I said slow"er", didn't say slow

HDDSuperClone vs ddrescue

Posted: Tue Aug 22, 2017 7:43 pm
by maximus
I was searching around and found this post. I would like to add some information.

First, I only helped with the ddrescue algorithm between versions 1.17 and 1.19. The original algorithm was very jumpy and would cause much head movement, and I assisted with making it better for real world recovery. Ddrescue version 1.19 and higher are much improved by this. That is the only credit I can take with ddrescue.

I learned much from analyzing ddrescue, but hddsuperclone is only based on the concept. All of the code and algorithms are very much my own. The idea of the different copy phases is a bit similar, but I take it to a higher level that is based on real world results.

As for being slower, it could be from some extra overhead. In my testing on a decent computer (2.7GHz Quad Core) I have so far found hddsuperclone to be right about the same speed as ddrescue when cloning a good drive with similar settings. I have noticed in certain tests that when using the more robust ATA passthrough mode, it can be up to 5% slower than ddrescue for read speed. But even if hddsuperclone is a bit slower, there are reasons that it is still better.

The first reason it is better is that the self learning head skipping algorithm will kick ass on a drive with a weak, damaged, or dead head. It will do its best to get the most from the good heads first, before digging into the bad head. This does not help as much on a drive with only a bad spot or just a few bad sectors, but can still be a good algorithm as bad spots can still be related to a head.

Second reason it is better, it makes a backup copy of the log file. This may not seem like a big deal, but shortly after I added this feature, someone sent me a log that was incomplete and cut off. When I asked, I was told that there was a power outage, and was sent the backup log. The backup log was complete, and a recovery could have been resumed from it. Had that been ddrescue, the missing part of the log would have been lost.

Third reason it is better, it always uses “direct” unbuffered reads and writes. With default settings, ddrescue allows the OS to use buffering for both reading and writing. For reading that can sometimes mean the OS performs unwanted retries, which is why the --direct option is recommended. Hddsuperclone uses different more direct system calls instead of the standard read, which is as good as or better than the --direct option of ddrescue. For writing, hddsuperclone always uses direct so there is no OS buffering. Ddrescue has as option to do this in recent versions, but you have to choose it. If the OS is buffering the write data, then it may not be written right away, and in the event of a power failure or crash, the data would not be written to the destination. The log file could possibly show that the data was recovered, but a small portion could actually not be written in this case. It is possible that this can be a difference in performance speed. But I don’t care if it makes hddsuperclone a little bit slower, I will stand by this choice as it makes it more robust and reliable.

If HDDSuperClone is 10% slower than ddrescue, I am not really concerned too much. If it is 20% or more slower in a case, then I may wish for more information on that recovery, to attempt to see why there is such a big difference.

HDDSuperClone vs ddrescue

Posted: Wed Aug 23, 2017 6:17 am
by jol
I only use software cloning with healthy drives.
I never use them for recoveries.
all tests that's done - mentioned above - was only after "hardware" recovery was completed and or healthy drives.
that said, then all the points mentioned above are not concerning me
but the speed "does" concerns me
I often use software after hardware was completed to make a second copy/image/clone
and the speed plays a big rule, from my point of view and my needs (time is money ;) )

maximus wrote:Source of the post If HDDSuperClone is 10% slower than ddrescue, I am not really concerned too much. If it is 20% or more slower in a case, then I may wish for more information on that recovery, to attempt to see why there is such a big difference.

Oh, I wish it was only 10%
in all the tests I made, it was about 30% slower which is a lot of time
example: a healthy 3.5" 1TB drive started @ 150-155MB/s (and dropped as we go to higher sectors (of course)) using ddrescue
when used HDDSuperClone (on the same healthy drive) its started @ about 105MB/s (and dropped as we go to higher sectors)

HDDSuperClone vs ddrescue

Posted: Wed Aug 23, 2017 7:52 am
by Jared
jol wrote:Source of the post a healthy 3.5" 1TB drive started @ 150-155MB/s (and dropped as we go to higher sectors (of course)) using ddrescue
when used HDDSuperClone (on the same healthy drive) its started @ about 105MB/s (and dropped as we go to higher sectors)


Are you actually timing it, or just going by the speed the software is reporting itself? Because I'm not sure how accurate that really is. I've found hddsuperclone to be quite fast.

HDDSuperClone vs ddrescue

Posted: Wed Aug 23, 2017 1:41 pm
by jol
Jared wrote:Are you actually timing it, or just going by the speed the software is reporting itself?

Oh ye, of course I have
part of the tests I made
Jared wrote:I've found hddsuperclone to be quite fast.

of course faster than clone under WIN OS, but not against ddrescue

HDDSuperClone vs ddrescue

Posted: Wed Aug 23, 2017 5:56 pm
by maximus
jol wrote:Oh, I wish it was only 10%
in all the tests I made, it was about 30% slower which is a lot of time
example: a healthy 3.5" 1TB drive started @ 150-155MB/s (and dropped as we go to higher sectors (of course)) using ddrescue
when used HDDSuperClone (on the same healthy drive) its started @ about 105MB/s (and dropped as we go to higher sectors)

Please do a simple test for me. When you have a drive that is that much slower with hddsuperclone than ddrescue, do a short test with /dev/null as the destination for both programs. You should only need several seconds or so to see the speed. Let me know what the speed difference is. That will rule out any difference in the writing process, and show only the read speed.