Ordinary database engine is deprecated but there is no simple mean to change database engine to Atomic for existing databases.

Possible options:
- ALTER DATABASE MODIFY ENGINE query.
- Flag that triggers migration at ClickHouse startup.

The latter should be easier to implement. 

const MergeTreeSettings & settings, std::string disk_type, const String & table_uuid,
    const String & part_name, const String & zookeeper_path_old)
{
    Strings res;
    String zero_copy = fmt::format("zero_copy_{}", disk_type);
    String new_path = fs::path(settings.remote_fs_zero_copy_zookeeper_path.toString()) / zero_copy / table_uuid / part_name;
    res.push_back(new_path);
    if (settings.remote_fs_zero_copy_path_compatible_mode && !zookeeper_path_old.empty())
    { 
        String old_path = fs::path(zookeeper_path_old) / zero_copy / "shared" / part_name;
        res.push_back(old_path);
    }
    return res;
}
bool StorageReplicatedMergeTree::checkZeroCopyLockExists(const String & part_name, const DiskPtr & disk)
{
    auto path = getZeroCopyPartPath(part_name, disk);
    if (path)
    {
        
        auto lock_path = fs::path(*path) / "part_exclusive_lock";
        if (getZooKeeper()->exists(lock_path))
        {
            return true;
        }
    }
    return false;
}
std::optional<String> StorageReplicatedMergeTree::getZeroCopyPartPath(const String & part_name, const DiskPtr & disk)