How do you back up and restore a ChromaDB persistent database?

import chromadb
import shutil
import os
from datetime import datetime

DB_PATH    = "./my_chroma_db"
BACKUP_DIR = "./backups"

# --- Backup strategy 1: Simple directory copy ---
# SAFE when: no active PersistentClient writes during the copy
os.makedirs(BACKUP_DIR, exist_ok=True)
timestamp   = datetime.now().strftime("%Y%m%d_%H%M%S")
backup_path = os.path.join(BACKUP_DIR, f"chroma_backup_{timestamp}")
shutil.copytree(DB_PATH, backup_path)
print(f"Backup saved to {backup_path}")

# --- Backup strategy 2: SQLite online backup (safe during reads) ---
import sqlite3

def backup_sqlite(db_path: str, backup_path: str):
    """SQLite online backup — safe even with active readers."""
    src = sqlite3.connect(os.path.join(db_path, "chroma.sqlite3"))
    dst = sqlite3.connect(os.path.join(backup_path, "chroma.sqlite3"))
    os.makedirs(backup_path, exist_ok=True)
    with dst:
        src.backup(dst, pages=100, progress=lambda s,p,r: print(f"Backed up {p} pages"))
    dst.close()
    src.close()
    # Also copy the HNSW index binary files
    for root, dirs, files in os.walk(db_path):
        for f in files:
            if f != "chroma.sqlite3":
                rel = os.path.relpath(root, db_path)
                dest_dir = os.path.join(backup_path, rel)
                os.makedirs(dest_dir, exist_ok=True)
                shutil.copy2(os.path.join(root, f), os.path.join(dest_dir, f))

# --- Restore ---
def restore_backup(backup_path: str, restore_path: str):
    if os.path.exists(restore_path):
        shutil.rmtree(restore_path)  # remove current
    shutil.copytree(backup_path, restore_path)
    print(f"Restored from {backup_path} to {restore_path}")

# Verify restored database
client = chromadb.PersistentClient(path=restore_path)
for col in client.list_collections():
    print(f"  {col}: {client.get_collection(col).count()} documents")