How to know which part file has errors when testing 7z split archives

[David]

Hi.

I had to transfer ~50GB of data from a server at the office to my home computer so I decided to 7zip that data in parts of 4GB and copy the 7zipped parts. After receiving them I Tested the file and got errors for multiple files in the Archive but unfortunately I can't tell in which part are those files.

ER: When testing, can you please specify in the output text to which Part(s) the file that failed belongs to?
ER: Can you please list a column in the 7zip main window file viewer to which part each file belongs to?

This will help us users to only re-copy the bad files.

Do you have a workaround for this?

Thanks!

[Igor Pavlov]

call from command line fro both copies of archive:

7z h *.7z.* > c:\crc.txt

then compare crc.txt files.

[David]

Hi! Thanks!
Yes, I did use the PS instead with Get-FileHash on both ends to check which one (more than one) did not copy right and re-started copying those files only. Didn't knew I could use 7z (while I suspect CRC may not be as safe as SHA-256).

It would be good to have an output but it seems that 7z splits "a whole file" not like RAR who knows which file starts/end on which packed file.

[Igor Pavlov]

The chance of false positive error for crc32 is 1 from 4 billions.
So it's safe to use crc32 to detect such errors.
7-Zip also suppports crc64 and sha, if you need more hashes.
But crc32 is simplest way for fast comparing to find failure.

[David]

GREAT!!! Thanks for answering!