Why does Time Machine folder sizes exceed physical capacity?

Question

I have a MAC G3 Server Serving multiple MACs as a Storage, Media Server, and Time Machine storage. These other external MACs are all running Version 10.8.3. Only the Storage server is running 10.5.8.
All of the extenal Macs use Time Machine to backup to the served Storage media volume called "Time Machine".
The physical size of the "Time Machine" volume is 2.0 TB.
Yet when I am on the G3 Server, and perform a "Get Info" on the "Time Machine" volume, and also the folder that contains the Server's backups, the stored capacities exceed the physical capacity of the drive to which the volume resides.
The single physical drive is 2.0 GB and only has one partition called "Time Machine". In the root directory of this volume there is the one folder called Backups.backupdb, and a .sparsebundle DMG file for each of the remote systems that are bing backed up by Time Machine.
Each of the sparsebundles are well below the dirve's physical capacity, but both the local server's backup folder (Backups.backupdb) and the G3 server's local volume "Time Machine" show a used capcity that well exceeds the physical capacity of the drive on which it resides.
For example, here is the information from "Get Info" on the Backups.backupdb folder on the "Time Machine" volume when viewed from all systems:
Kind: Folder
Size: 3,456,930,478,415 bytes (3.46 TB on disk) for 122,254 items
But the Physical Volume "Get Info" shows this:
Kind: Volume
Capacity: 2.0 TB
Available: 169.92 GB
Used: 3,456,930,478,415 bytes (3.46 TB on disk) for 122,254 items
(NOTE: this is identical to the size
My guess is that there is some sort of deduplication involved.
If so, I would like to know the type of deduplication is performed?
Is it File Level deduplication, Block Level, or Content Level?
Also, is the deduplication inhererant on the volume (File System) level, or only specifically for Time Machine, via symbolic links?
Thank you in advance.
Jeff Cameron

Answer 1

This is due to the way Time Machine stores files. While there is only one copy of each version of each file stored, there are multple links to that file, and each link is reported in Get Info at its restored size.
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