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How is deduplication working?


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on a ESXi server I had troubles with the snapshot of one VM (also when I do snapshots from the Vmware interfac, so not an Nakivo issue)
Since I don't have the possibility to take the server offline, I removed the VM from the backup Job but I left the data on the repository.
Then I added the VM directly as "physical server" to my inventory and created a new backup jop to the same repo.
Bevor I started the new Job, I had 1.03 TB free space, the VM has a disk size of 200 GB and about 150 GB used.
After the new Backup I had 900 GB of free space (100 GB used by new backup).

According to your website you have "Global deduplication for economical storage space utilization" in your product.

So why does a second backup of the same VM take this much space? I just use a diffrent way to backup the same data...


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During backup (it does not matter VM or physical) all data is divided for blocks and stored in the repository. In case some blocks appear to be similar, deduplication works and only one block is saved in the repository. It seems that in this case saved data from VMDK file and directly from VM disk has different layout (contains some additional service information or shift for example). In this case saved blocks are different and will not be deduplicated.

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