da.from_zarr does not use shards (da.from_array does)
Author: joshua-gouldCreated Sep 8, 2026Updated Sep 8, 2026
Labelsneeds triage
Sharded zarr arrays - da.from_array sets dask array chunk size correctly, but da.from_zarr does not.
import numpy as np
import zarr
import dask.array as da
zarr.create_array("test.zarr", data=np.arange(100).reshape((10, 10)),
chunks=(2, 2), shards=(10, 10))
assert da.from_array(zarr.open("test.zarr")).chunksize == (10, 10) # works
assert da.from_zarr("test.zarr").chunksize == (10, 10) # fails
Environment:
- Dask version: git main
- Install method: source
Source: dask/dask