How can a folder have much larger `size on disk` than `size`?

Question

I have a folder on a NTFS network drive. I had copied it over from my local NTFS drive. Its displayed size on the network drive is totally confusing to me:

Size:           1,34 GB
Size on Disk:   12,2 GB

How can there be a tenfold discrepancy between size and size on disk? And what is the true size now?

try defragmenting the drive and check size again...may be its the way in which a file is saved across different sectors of a HDD. You could also try deleting it and copying again — David Kent, Mar 07 '21 at 08:00
well its not my drive, guess I'll talk to the admin about it — csstudent1418, Mar 07 '21 at 08:04
wait so u copied a file from your local drive to the network drive ? — David Kent, Mar 07 '21 at 08:07
here you go: https://superuser.com/questions/704218/why-is-there-such-a-big-difference-between-size-and-size-on-disk — David Kent, Mar 07 '21 at 08:11
Around 12.000 files. Thanks for the link. I'm not sure if the top answer there applies here as it talks about FAT instead of NTFS, but I guess it will be in principle the same reason (I ain't no filesystem expert). — csstudent1418, Mar 07 '21 at 08:19
It might just be a question of the network share reporting the consumed space incorrectly. I’ve seen that on some older versions of Synology NAS (but that’s probably not what you’re using). What system does the share come from and what does it report about consumed space itself when looking at its local disks? — StarCat, Mar 07 '21 at 09:12
@StarCat I checked using command du (disk usage) and it gave me 1.4G . Could the Size on Disk windows gives me be erroneous? — csstudent1418, Mar 07 '21 at 11:13
Well, Windows is just reporting what it receives from Samba. That value might be erroneous. I see you've found the solution yourself. — StarCat, Mar 07 '21 at 12:03

score 0 · Accepted Answer · answered Mar 07 '21 at 11:40

0

It turns out the smb allocation roundup size was (and I guess by default is) set to 1048576 (i.e. 1MB), so even small files appear to have that size.

This was reported here as well. Lowering the value to 131072 as suggested there resolves the issue.

answered Mar 07 '21 at 11:40

csstudent1418

411

How can a folder have much larger `size on disk` than `size`?

1 Answers1