[SOLVED] Help - Lacie Hard Drive is Saying that it has 270 GB Space when it should be 1TB

Sep 20, 2020
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Hi everyone,

I just purchased a new Lacie 4 TB external Hard drive and I copied 3 TB of files from a Freecom 3 TB external hard drive and after the files were successfully copied to the Lacie drive it said it had only 270 GB space available when it should be at least 1TB.

Does anyone know what this could be happening? It was formatted in ExFat on my mac 2019 computer.

Many thanks.
 
Solution
wo things that comes to mind:
  • 1TB is NOT counted as 1*1^12 bytes (because 1kB counts 1024 bytes, and it adds up for larger volumes).
  • Small files takes space too. Therefore may small files will fill more space than the sum of their size.
That was my first thought too. A 4TB drive should have approximately 4,000,000,000,000 bytes of storage, but Windows uses the kilo, mega, giga, and tera prefixes to refer to groups of 1024, resulting in such a drive appearing as having a little under 3.64TB to Windows. It's the same amount of usable space, just referred to in a different way.

I noticed just now that this was apparently for MacOS though, and I believe Macs have switched to using the same 1,000-based prefixes as...
Two things that comes to mind:
  • 1TB is NOT counted as 1*1^12 bytes (because 1kB counts 1024 bytes, and it adds up for larger volumes).
  • Small files takes space too. Therefore may small files will fill more space than the sum of their size.
 
wo things that comes to mind:
  • 1TB is NOT counted as 1*1^12 bytes (because 1kB counts 1024 bytes, and it adds up for larger volumes).
  • Small files takes space too. Therefore may small files will fill more space than the sum of their size.
That was my first thought too. A 4TB drive should have approximately 4,000,000,000,000 bytes of storage, but Windows uses the kilo, mega, giga, and tera prefixes to refer to groups of 1024, resulting in such a drive appearing as having a little under 3.64TB to Windows. It's the same amount of usable space, just referred to in a different way.

I noticed just now that this was apparently for MacOS though, and I believe Macs have switched to using the same 1,000-based prefixes as hard drives when referring to file sizes and drive capacities.

And if these files were in fact copied from a 3TB drive, then any potential difference like that should apply to that drive as well, and there should still be at least 1TB of usable space available (or at least 931GB as reported by Windows), not just 270GB. So either that other drive was larger than 3TB, or perhaps some cloning method was used to copy the files over that left some space on the new drive unformatted, or something else along those lines.

So, questions worth asking... Do you still have the original "3TB" drive, and if so, how much total space is it reported as having, and how much of that space is reported to be used and free? And the same for the new drive?

And also, how did you transfer the files from the old drive to the new one? By just copying them over through the file explorer (I believe Finder on a Mac), or by using some other software to clone them from one drive to the other?
 
Solution
I believe that exFAT is less efficient with storage space than NTFS when it comes to large volumes. In fact the cluster size for 4TB exFAT volumes is 1MiB whereas it is 4KB for NTFS. This means that, on average, each file has 512KB of slack space under exFAT, and only 2KiB under NTFS.

https://en.wikipedia.org/wiki/ExFAT

How many files are on your drive? Multiply that number by 0.5 MB.
 
Last edited:
Sep 20, 2020
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Thanks everyone for your detailed responses.

Cryroburner yes I still have the original Freecom 3TB External Hard drive is shown to have 3TB storage and it is showing 123.96 GB of free space from the 3 TB storage capacity. Just one further thing its formatted in Mac OS Extended (Journaled) and the new Lacie 4 TB External hard drive is formatted in EXFat.

The new Lacie 4 TB External hard drive is reported to have 4TB storage capacity and it says it has used 3.73 TB. It says it has 267.78 GB free space available.

And with regards to how I copied the files over I simply selected all the files and copied and pasted them into the new Lacie 4 TB External Hard drive. Is there a quicker way to do it? That gets faster transfer speeds?

I believe that the new Lacie 4 TB drive is USB 3 while the Freecom 3 TB drive is USB 2. It took me about 72 hours to transfer all the files!

Also does anyone know the best file format to format an External Hard drive for Mac? I only want to use the drive on a Mac computer but want the best option.

Many thanks.
 
Sep 20, 2020
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Just wanted to update this post just in case anyone else has the same problem. I found the solution and the issue was being caused because the original Freecom drive was formatted in a different file format then the destination drive once I reformatted the Lacie Drive so that it was also using Mac OS Extended (Journaled) the copied files took up the exact same storage space on the new Lacie Drive as the original drive it was copied from.