Explain what to do if downloading PDB mmCIF files is too slow.

PiperOrigin-RevId: 424887480
Change-Id: I4ea7a2aba785d037f49cf22c503ebebe3303e468

scripts/download_pdb_mmcif.sh

@@ -40,6 +40,10 @@ RAW_DIR="${ROOT_DIR}/raw"
 MMCIF_DIR="${ROOT_DIR}/mmcif_files"
 
 echo "Running rsync to fetch all mmCIF files (note that the rsync progress estimate might be inaccurate)..."
+echo "If the download speed is too slow, try changing the mirror to:"
+echo "  * rsync.ebi.ac.uk::pub/databases/pdb/data/structures/divided/mmCIF/ (Europe)"
+echo "  * ftp.pdbj.org::ftp_data/structures/divided/mmCIF/ (Asia)"
+echo "or see https://www.wwpdb.org/ftp/pdb-ftp-sites for more download options."
 mkdir --parents "${RAW_DIR}"
 rsync --recursive --links --perms --times --compress --info=progress2 --delete --port=33444 \
   rsync.rcsb.org::ftp_data/structures/divided/mmCIF/ \