issue_comments: 598790404

Hi all. I am looking into this issue, trying to figure out if it is still a thing. I just tried @chrisbarber's MRE above using xarray v 0.15.

python import xarray as xr ds=xr.Dataset({'foo': (['bar'], np.zeros((505359,)))}) ds.to_zarr('test.zarr', mode='w') ds2=xr.open_zarr('test.zarr') ds2.to_zarr('test2.zarr', mode='w') This now works without error, thanks to #2487.

I can trigger the error in a third step: python ds3 = ds2.chunk({'bar': 10000}) ds3.to_zarr('test3.zarr', mode='w')

raises NotImplementedError: Specified zarr chunks (63170,) would overlap multiple dask chunks ((10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 10000, 5359),). This is not implemented in xarray yet. Consider rechunking the data using `chunk()` or specifying different chunks in encoding.

The problem is that, even though we rechunked the data, chunks key is still present in encoding. ```python

print(ds3.foo.encoding) {'chunks': (63170,), 'compressor': Blosc(cname='lz4', clevel=5, shuffle=SHUFFLE, blocksize=0), 'filters': None, '_FillValue': nan, 'dtype': dtype('float64')} ```

This was populated with the variable was read from test.zarr.

As a workaround, you can delete the encoding (either just the chunk attribute or all of it): python ds3.foo.encoding = {} ds3.to_zarr('test3.zarr', mode='w') This allows the operation to complete successfully.

For all the users stuck on this problem (e.g. @abarciauskas-bgse): - update to the latest version of xarray and then - delete the encoding on your variables, or overwrite it with the encoding keyword in to_zarr.

For xarray developers, the question is whether the chunk() method should delete existing chunks attributes from encoding.