File Copy Verification

English Support for Syncovery on Windows.
mazcredi
Posts: 7
Joined: Mon Jun 28, 2021 6:30 pm
Location: New York City

File Copy Verification

Post by mazcredi »

Hello,

What methodology does the "Verify copied files" option under the "Files" tab use to assure a successful copy?
Please excuse me if this is covered elsewhere but a search of the forum and the documentation section of the site did not turn up much.

Thank you

tobias
Posts: 1604
Joined: Tue Mar 31, 2020 7:37 pm

Re: File Copy Verification

Post by tobias »

Hello,
it depends on what storage location the two sides of the sync profile are.

The default behavior is that "verify copied files" copies the file back in the opposite direction and compares the content against the original file. So every single Byte is compared. This normally doubles the use of network or Internet bandwidth.

Some cloud services support MD5 checksums, which are then used instead of re-downloading the file.

Most cloud services ensure file integrity during upload, so that "verify copied files" is not really necessary. File integrity is also ensured thru the HTTPS protocol.

If you copy between your own servers or other machines, you can use the Syncovery Remote Service to generate MD5 checksums remotely, if you want to save bandwidth. Please see
https://www.syncovery.com/remoteservice/

Redwood
Posts: 46
Joined: Wed Jun 02, 2021 12:44 pm

Re: File Copy Verification

Post by Redwood »

tobias wrote:
Mon Jun 28, 2021 8:32 pm
Some cloud services support MD5 checksums, which are then used instead of re-downloading the file.
It does not work with Google Drive
viewtopic.php?f=3&t=274
Also it does not remember results of the verification if encryption is enabled
viewtopic.php?f=3&t=281

mazcredi
Posts: 7
Joined: Mon Jun 28, 2021 6:30 pm
Location: New York City

Re: File Copy Verification

Post by mazcredi »

tobias wrote:
Mon Jun 28, 2021 8:32 pm
If you copy between your own servers or other machines, you can use the Syncovery Remote Service to generate MD5 checksums remotely, if you want to save bandwidth. Please see
https://www.syncovery.com/remoteservice/
Thank you for your reply. Yes, this is my situation, copy between own servers. Let's say a file server was migrated from one device to another but the "verify copied files" option was not checked during the initial job to save time. Is there a way to perform this retroactively?

tobias
Posts: 1604
Joined: Tue Mar 31, 2020 7:37 pm

Re: File Copy Verification

Post by tobias »

Hello,
yes, it's called "binary verification of existing files" and you can find it under Comparison->More.

Typically you would do this only once and then remove the option. If you want to keep it, be sure to choose "Remember Results" to avoid re-comparing all the files every time.

Syncovery will re-copy any files which failed the verification, and log the failed verification in the log file.

mazcredi
Posts: 7
Joined: Mon Jun 28, 2021 6:30 pm
Location: New York City

Re: File Copy Verification

Post by mazcredi »

tobias wrote:
Wed Jun 30, 2021 8:35 pm
Hello,
yes, it's called "binary verification of existing files" and you can find it under Comparison->More.
oh nice, this tool is so flexible and full of features. Been using it for years and still find new stuff.
tobias wrote:
Wed Jun 30, 2021 8:35 pm
Syncovery will re-copy any files which failed the verification, and log the failed verification in the log file.
So since I am doing this retroactively after a previous run, I am not interested at this time in copying any files to the right side whether because they failed the binary comparison or because the file on the right side is no longer there. All I want really is a report of the binary comparison results. I seem to achieve this by doing an Attended Run and cancel after the preview. The resulting log file can serve as the report although I can't seem to suppress all copies. I tried pulling this off by setting the "Copy only X files per run" to zero but it seems to require at least 1. At any rate I may be able to live with the resulting log file.

However the results on one of my test runs came back with this:
"Total Binary Comparisons: 21181, Successful: 21181, Skipped: 9"
The problem is that I don't know why it skipped those 9 files and which ones they are.

Thanks for your continued support.

tobias
Posts: 1604
Joined: Tue Mar 31, 2020 7:37 pm

Re: File Copy Verification

Post by tobias »

Hello,
yes you can just let it do the comparison phase and cancel the preview to get the comparison results. Or you could change all file actions in the Preview to "Leave alone".

Skipped means that it had previously compared them due to the "Remember Results" feature.

tobias
Posts: 1604
Joined: Tue Mar 31, 2020 7:37 pm

Re: File Copy Verification

Post by tobias »

Hello,
another detail: Skipped can also mean that empty files (0 Byte files) were skipped.

mazcredi
Posts: 7
Joined: Mon Jun 28, 2021 6:30 pm
Location: New York City

Re: File Copy Verification

Post by mazcredi »

Thanks Tobias but unfortunately the log file does not specify which files were skipped unless I am missing something. Any way to find out which files were skipped otherwise?

tobias
Posts: 1604
Joined: Tue Mar 31, 2020 7:37 pm

Re: File Copy Verification

Post by tobias »

Hello,
if they are not mentioned in the log, they are empty files. Empty files don't need to be verified specially.

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