Question backup drives

Dennis Hagans

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Hey Guys

I have a problem, I have two backup drives, a best Buy 1TB Passport and a 1TB SATA from a laptop that died
they both come up as 931 GB Both are USB 3.0 external drives

They are labeled Backup drive D: and Backup Drive E:

When I look under My PC it tells me the size of C: D: and E: and also how much space is left on each drive

No matter what software I use I cannot get them to match, I use Teracopy, Explorer, Unstoppable copy, and HDcopy

Backup drive E: no matter what I use is always 3GB less than Backup Drive D:

Backup drive D: is showing 151GB free of 931, Backup Drive E: is showing 154GB free of 931

I select all of the files/folders on D: and then copy/paste them to E:

Any help would be appreciated.
 

Lafong

Respectable
"Match" what exactly?

Exact remaining space? Measured by what?

Exact used space? Measured by what?

To the byte level?

"Size" in File Explorer?

"Size on disk" in File Explorer?

Files found on one cannot be found on the other after a copy operation?
 

Dennis Hagans

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I have 2 external hard drives, one is a USB 3.0 Best Buy Passport 1TB

The other is a SATA drive taken out of a dead motherboard laptop, it is 2.5 inches I have a USB 3.0 adaptor that plugs onto this drive and I can use it in a USB 3.0 port as an external drive, it also is a 1TB hard drive

Both drives when opened in Explorer read 931 GB

The passport drive reads 220 GB free of 931 GB available

The external SATA Drive reads 154 GB free of 931 GB available

The passport is a backup drive of all of my files, pictures, videos, music, Downloads, Documents, and a Folder called all bible apps. it is a copy and paste backup of all my files I wish to have a backup of.

The external SATA drive is the same size 1TB with 931 GB available and right now 154 GB free of 931

this is how they read when looking at them in explorer in windows 10.

I have just gone through the passport and gotten rid of duplicates, however when I try to copy everything from the passport drive to the SATA drive when I get done there is always 3 GB freer on the SATA drive than on the Passport, they are both 1TB they both read 931 GB available.

yet when I copy and paste everything from the passport drive to the SATA drive the SATA always shows 3 GB more free than the passport that I have tried to copy to the SATA.

I get the passport drive like I want it, and then copy and paste everything to the SATA drive and I still end up with the SATA showing 3GB more free space than on the passport that I just copied and pasted to the SATA

passport 1TB 931GB available 220 GB Free according to windows explorer

SATA drive 1TH 931 GB available 154GB free according to windows explorer

I have updated the passport I have not copied the updated files/folders to the SATA yet

Hoping for an answer here first. (I format the SATA and then do the copy and paste)

I have used Terecopy, Explorer, unstoppable copy, and hdcopy as my copy programs it does not matter which one I use to copy and paste from the passport to the SATA, it always shows the SATA as having 3 GB more available than the passport drive.

if both drives are 1TB and both drives read as 931 GB available then a direct copy from one drive to the other should have then both reading the same exact amount free when the copying is done.


Thanks in advance, I tried to make it plainer.
 
When I look under My PC it tells me the size of C: D: and E: and also how much space is left on each drive

No matter what software I use I cannot get them to match, I use Teracopy, Explorer, Unstoppable copy, and HDcopy
The amount of data being taken up by the files is never going to match between partition/drives unless you do a low-level clone. There's always going to be some fragmentation on the partition which will throw this off. Since pieces of files will always take a sector size at the minimum (either 4KiB or less commonly 512 bytes) and if the file is significantly bigger than the sector size, the amount of space the file takes up is always going to be different.

Don't rely on how much data the files take up to verify that the backup or copy was successful. Use a file synchronization tool like FreeFileSync.
 

Lafong

Respectable
Still a bit confused.

Several times you refer to a 3 GB discrepancy.

Then you say there is a 66 GB discrepancy (220 minus 154).

Sector sizes can vary from one drive to the next. Slack space may come into play. File Explorer can't always be taken literally.
 

Dennis Hagans

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The reason for the new discrepancy

"I have updated the passport I have not copied the updated files/folders to the SATA yet "

Last night I went through the passport drive getting rid of duplicates, that is why there is a new discrepancy.

What I am saying is that when I copy the passport drive everything to the SATA drive, every time no matter what copy program I use there is a 3GB discrepancy where the SATA reads in explorer as having 3GB of space more than the passport.

When I copy, I snag all of the folders on the Passport ctrl-A then ctrl-C then switch to the SATA Drive with nothing on it "fresh format" and ctrl-V

There are 6 folders on the passport, I grab all of them ctrl-A, then ctrl-C, switch the empty SATA drive, and ctrl-V.

it should be straight forward everything on D: is copied to E:

so that I have two backup external drives that are exactly the same, if one of them goes down, I still have the other with everything on it.

Years of experience in forgetting to back stuff up has taught me, backup, backup, backup.

Thank you Guys.
 

Dennis Hagans

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Well that is kinda hard, in my latter years I have gotten OCD where I want stuff to be as perfect as possible, I know I have two drives of the exact same capacity, and I now have the d: drive Ppassport with just 6 folders, so that when I copy all 6 folders to the E: drive SATA, they should match, line right up.

And it is just bugging me that there is a difference when there should not be one.

1TB passport explorer says 931 GB available

1TB SATA explorer says 931 GB available

copy 6 folders ctrl-A, ctrl-C switch to the empty SATA ctrl-V, and all 6 folders copy but with a 3GB difference that should not be.

It could be that explorer is not reporting the capacity correctly and that is the reason for the difference I guess I will have to live with it. lol

Thank you guys for the answers.
 

Lafong

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And it is just bugging me that there is a difference when there should not be one.
I back up entire drives or entire folder structures in multiple ways regularly.

I have seen occasional cases where a simple file count on a source drive differs significantly from the file count on the destination drive after a supposed 100% copy via drag and drop. By several thousand out of roughly 100,000. This is a data drive, no Windows components.

I regularly see cases where the file count does not match by a much smaller amount.

But I have never encountered a case where a file on the source could not in fact be found on the destination if I actually went looking for it.

Make of that what you will.

Did several thousand files actually not get copied? I don't know. I doubt it. I did not panic and start drilling into folders to try to find out.

I take the discrepancy (in my case) to just be some peculiarity in how File Explorer counts and measures. Junctions maybe? I don't know much about disk engineering.
 

USAFRet

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I back up entire drives in multiple ways regularly.
Yep.
Full drive backups, via Macrium.
All automated, on a schedule.

Nothing forgotten or missed.

 

Dennis Hagans

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I just installed Macrium free personal backup, I had just been copying all of my files/folders as far as what I have downloaded and collected, I did not have a backup program but I do now, thank you for sharing about Macrium.

I need to get a drive to use as the backup drive for Macrium to have somewhere to back up to.
 

Lafong

Respectable
You can use internal or external or both to store the image.

For a standard "full image", Macrium will create a file circa 60 percent of the size of the occupied space on the partitions you choose to include in the image. You choose which partitions. One big file with an mrimg extension.

You can make a full image with maybe 7 mouse clicks, accepting defaults.

The image itself can be copied and moved around like any other file. It's a valuable file in itself, so you'd probably want to back it up.
 
May 25, 2022
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Hey Guys

I have a problem,...

Backup drive E: no matter what I use is always 3GB less than Backup Drive D:

Backup drive D: is showing 151GB free of 931, Backup Drive E: is showing 154GB free of 931

I select all of the files/folders on D: and then copy/paste them to E:

Any help would be appreciated.
Are both drives formatted identically? Meaning using the same size allocation unit?
 

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