Linux Container in ACI will get around 50 GB of storage where the containers images are also stored.
That storage is shared by all the containers in the container group. If you create a empty directory volume, that also will be provided from the same space.
If you are looking to store around 200 GB, then it is recommended to use Azure files. You can mount azure file share as volume to the container, please refer this document for more details. Currently we cannot attach azure files to the windows containers in ACI.
Source : MSDN Thread Link