Copy partition size discrepancy

[TeraByte Support]

a copy operation is read/write so doubles, if you validate it will be more.

[Muad'Dib]

Isn't a backup also read/write?

[TeraByte Support]

it's compressed, you don't really know the size, a copy is known, read data, write data, data to process...

[Muad'Dib]

I don't mean to keep arguing, but this still makes no sense to me. I always set the Compression level to "None" when I run Backup. So with that setting why would the backing up a 500GB drive process less data than copying a 500GB drive?

FWIW, I backup drives on multiple machines quite frequently, so I'm very familiar with the numbers that get displayed when backing up. However, I very rarely run the Copy routine (almost exclusively when I'm swapping drives), so I'm not as familiar with those numbers.

[TeraByte Support]

It's the way it works, backup will show source size plus validate (adjusted on changes only as it proceeds), copy will show both reads and writes (plus validates). If you only did one side the progress bar would pause with zero through-put as it did one side.

[Muad'Dib]

YesAndNo: I still don't understand TeraByte Support's explanation, but since I rarely use Copy, I'm not going to worry about it.

Have you tried running Backup (with no compression) on the drive and compared the time it takes to run Copy on the same drive? If the time is similar between the two methods, then the number of bytes "processed" really doesn't matter. However, if Copy takes twice as long as Backup then there's something that needs to be explained more clearly (at least to me!).

When you get a chance, post what you find out.

[TeraByte Support]

if you think processing 2TiB of data is taking too long on USB<->USB, you can try the other performance preset and compare the results.

[YesAndNo]

YesAndNo: I still don't understand TeraByte Support's explanation, but since I rarely use Copy, I'm not going to worry about it...

No, I don't understand either to be honest given that the original explanation was that it was double because of validating. I'll have to try the same operation with validation now and see it it shows quadruple the size which it would have to if both explanations are correct.

[YesAndNo]

YesAndNo: I still don't understand TeraByte Support's explanation, but since I rarely use Copy, I'm not going to worry about it...

No, I don't understand either to be honest given that the original explanation was that it was double because of validating. I'll have to try the same operation with validation now and see it it shows triple (or maybe quadruple) the size which it would have to if both explanations are correct.

[Muad'Dib]

The "size" (number of bytes processed) is irrelevant. What matters is how much time it takes. Without compression, Backup and Copy should take about the same amount of time (for the same size drive). And Byte-for-Byte Validation should take about twice that for either method.