export SPACK_USER_CONFIG_PATH=~/.spack
export SPACK_USER_CACHE_PATH=/tmp/spack-$USER

spack config edit config
config:
  install_tree:
    root: /scratch/lustre/home/rona1043/.spack
  source_cache: /tmp/spack-rona1043/source

spack env create -d test
spack env activate test