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Restoration Progress % Issue

Posted: Wed May 01, 2013 8:07 pm
by Lewpy
I have two identical 8GB USB memory sticks.
I took a Device Mode backup of one of them this morning, using the .img.gz format.
Now when I try to restore the image to the other memory stick, the progress bar goes beyond 100% :o
I let it go up to 200% before stopping it, but I am not sure if the restoration process was a success.
I will take uncompressed Device Mode backups of each stick and compare them.

Re: Restoration Progress % Issue

Posted: Wed May 01, 2013 8:17 pm
by Lewpy
I left it running again, and this time it completed the restoration at a point somewhere over 200% 8-)
So I had just cut it off a bit early before.
Still a bit curious as to how it calculates the % progress number.
The Compressed image is 5.86 GB (6,298,122,495 bytes)
The Uncompressed image is 7.46 GB (8,019,509,248 bytes)
So not a 2:1 ratio there.

I will backup the restored USB stick, and run a binary compare on the uncompressed files :)

Re: Restoration Progress % Issue

Posted: Wed May 01, 2013 8:28 pm
by Lewpy
Both files are identical, so it did correctly complete the restoration process :D
I forgot to mention this is with the [currently] latest version 1.61

Re: Restoration Progress % Issue

Posted: Thu May 02, 2013 7:37 pm
by Alex
Thanks for reporting. I will take a look at this. Maybe there is something wrong with my progress calculation, because gz file format only stores file size up to 4Gb, as the field is to small to hold larger values.

Re: Restoration Progress % Issue

Posted: Thu May 02, 2013 7:42 pm
by Lewpy
Ah, yes, I do have the "ignore 4GB gzip check" option enabled :oops:

Re: Restoration Progress % Issue

Posted: Mon Sep 29, 2014 3:52 pm
by AntiqueTech
Any update on this? I am using the command line version and consistently getting 216% as my final completion percentage. I have used versions 1.58 and 1.69 with the same results. I have seen this when restoring to 8 GB and 16 GB flash drives. The command line I am using in 1.69 is:

usbitcmd r <dev#> file.img.gz /g /d /s /i /b:2048

The gzip file size is 5.34 GB (5,736,902,439 bytes). The resulting flash drive used space is 7.02 GB (7,541,682,176 bytes).

I get the same results without the /s option and without the /i option. I also get the same results regardless of the value for /b.

Re: Restoration Progress % Issue

Posted: Mon Sep 29, 2014 7:27 pm
by Alex
I'm afraid, there will be no real solution to this issue. Because the gzip file format only contains a 32 bit value for the uncomressed file size, all images larger than 4 GiB have an invalid size information stored in the gzip file. As uncompression is done on-the-fly during restore, there is no chance to say how large the uncompressed image will be. Because of that, the percentage value can be inaccurate. The only option would be to calculate based on the maximum device size, but this will lead to completion values below 100%, when restoring smaller images to larger flash drives.

Re: Restoration Progress % Issue

Posted: Mon Sep 29, 2014 11:10 pm
by AntiqueTech
Thank you for the clear explanation.