Verify data checkbox on new drives seems not to work

[steffenmand]

Hi,

 

Just noticed that when creating a new drive, the "Verify data" checkbox seems not to take effect when making the new drive.

 

So i have to manually activate Upload Verification

 

Windows 10

.827

 

Might be fixed in a new version

 

Thanks!

[Choruptian]

I might be wrong but I think they are separate things. "Verify data" does cryptographic validation (SHA-1) to ensure that the data hasn't been modified lying on the cloud for a while. "Upload verification" actually re-downloads the data to ensure you uploaded the right content as you go.

 

EDIT: A quick test seems to corroborate this as unticking "Verify data" yields "ValidationAlgorithm: None" in Drive details.

[Christopher (Drashna)]

Choruptian is correct.

 

There are two main "checks" here: 

• Checksum verification
• Upload verification

And these two things do entirely different things. 

 

Checksum verification adds a small block to each and every data block.  This is a checksum of the data, to verify it's integrity.  If there is a problem the drive will actually error out, so that you don't grab corrupted data.  

 

Then there is upload verification. This verifies that the data has been properly uploaded.  It re-downloads the data after it is uploaded, compares it and then either re-uploads it again, or "clears" it from the cache, moving onto the next chunk. 

 

 

Some providers "require" upload verification (such as Amazon Cloud Drive), but most do not.  And upload verification adds significant overhead, as it's redownloading everything that gets uploaded.