# \[ANN\] SmallZarrGroups.jl - Save and load hierarchy of arrays and metadata

**URL:** <https://discourse.julialang.org/t/ann-smallzarrgroups-jl-save-and-load-hierarchy-of-arrays-and-metadata/96394>\
**Category:** Package Announcements\
**Created:** [March 21, 2023, 2:36pm UTC](https://discourse.julialang.org/t/ann-smallzarrgroups-jl-save-and-load-hierarchy-of-arrays-and-metadata/96394 "2023-03-21T14:36:01Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![nhz2](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nhz2/32/44428_2.png) [@nhz2](https://discourse.julialang.org/u/nhz2)\
**Post date:** [March 21, 2023, 2:36pm UTC](https://discourse.julialang.org/t/ann-smallzarrgroups-jl-save-and-load-hierarchy-of-arrays-and-metadata/96394/1 "2023-03-21T14:36:01Z")

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Hello all,

I was looking for a way to save snapshots of my simulation state to disk for restart, archival, and analysis purposes. I wanted these snapshots to be easily readable from python. Lastly, I didn’t care about write performance, I was only saving about 1 MB per snapshot, but I wanted a format that was efficient with disk space and could be quickly read in multi-threaded analysis scripts.

This lead me to the zarr format and Zarr.jl and  
zarr-python.

Zarr.jl is a great package, however, the main issue I have with it is that it doesn’t have a 1.0 release and is missing zip file support.

To solve my issues, I created a zarr reading and writing package with a much narrower scope than Zarr.jl:

> **[GitHub - medyan-dev/SmallZarrGroups.jl: In memory hierarchy of arrays and...](https://github.com/medyan-dev/SmallZarrGroups.jl)**
>
> In memory hierarchy of arrays and attributes loaded from disk or to be saved to disk with Zarr. - GitHub - medyan-dev/SmallZarrGroups.jl: In memory hierarchy of arrays and attributes loaded from di...

I would greatly appreciate feedback on the current API before it becomes fixed when version 1.0 is released.

The following tests show examples of the current API:

> <https://github.com/medyan-dev/SmallZarrGroups.jl/blob/main/test/test_simple-usage.jl>

Nathan