# Does DVC duplicate dataset in storage blobs when the same dataset is used in different tags?

**URL:** <https://discuss.dvc.org/t/does-dvc-duplicate-dataset-in-storage-blobs-when-the-same-dataset-is-used-in-different-tags/938>\
**Category:** Questions\
**Created:** [October 29, 2021, 10:35am UTC](https://discuss.dvc.org/t/does-dvc-duplicate-dataset-in-storage-blobs-when-the-same-dataset-is-used-in-different-tags/938 "2021-10-29T10:35:58Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![subhankar](https://avatars.discourse-cdn.com/v4/letter/s/ecb155/32.png) [@subhankar](https://discuss.dvc.org/u/subhankar)\
**Post date:** [October 29, 2021, 10:35am UTC](https://discuss.dvc.org/t/does-dvc-duplicate-dataset-in-storage-blobs-when-the-same-dataset-is-used-in-different-tags/938/1 "2021-10-29T10:35:58Z")

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Hi,

Suppose I have a dataset of 5 GB (images and jsons). I version this dataset using DVC and give a tag name dataset\_1. I push the dataset to S3.

Now I add a new dataset of 7GB (images and jsons) to the old dataset, take a tag out called dataset\_2 and push to the same S3 bucket. So dataset\_2 tag contains the old 5GB and the new 7GB data.

How much storage space is being taken by S3. Will it be 12GB (5 +7) or 15 GB (5 + (5 + 7))?  
In other words, is the older dataset being duplicated in S3?

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**Author:** ![Paffciu](https://avatars.discourse-cdn.com/v4/letter/p/d07c76/32.png) [@Paffciu](https://discuss.dvc.org/u/Paffciu)\
**Post date:** [October 29, 2021, 10:55am UTC](https://discuss.dvc.org/t/does-dvc-duplicate-dataset-in-storage-blobs-when-the-same-dataset-is-used-in-different-tags/938/2 "2021-10-29T10:55:51Z")

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Hello @subhankar,  
The answer to your question depends on how are your datasets stored. DVC asserts granularity on a file level - which means that if given files shows up in different datasets, it will still be stored as single file in the remote. You can read a bit on our cache structure here: [https://dvc.org/doc/user-guide/project-structure/internal-files#structure-of-the-cache-directory](https://dvc.org/doc/user-guide/project-structure/internal-files#structure-of-the-cache-directory)

So if your datasets are directories containing files, your data will take (5+7) GB (assuming that none of the files repeat between those two versions - if they do it’s even better, because DVC will know to store only one copy.

If your dataset is some kind of archive (for example a `.tar` file) DVC will store each file separately, which means that your remote will have 5 + (5+7) GB.