Optimize search through all drives

Question

Hi, I need to implement an efficient search through user's disks. I would really like to search multiple disks in parallel to speed up the process, but at the same time, avoid using too much CPU resources.

I've already implemented a directory search that will scan a directory first superficially (only the current directory), and then, if necessary, will also scan subdirectories. Here is an example:

      public async Task SearchAsync(SearchOptions searchOptions)
      {
		  // Look in searched directory
          await ShallowSearchAsync(searchOptions);

		  // If nested search needs to be performed, look also in subdirectories
          if (searchOptions.Filter.IsNestedSearch)
          {
				await Task.Run(async () =>
	            {
	                foreach(subdirectory in EnumerateSubDirectories())
					{
						await subdirectory.SearchAsync(searchOptions);
					}
	            }, searchOptions.Token);
          }
      }

	public async Task ShallowSearchAsync(SearchOptions searchOptions)
	{
		// Here we look through directorie's files 
		// and filter out those that do not meet the search conditions
	}	

If you have any ideas on how to optimize my search method, I'd be glad to hear them.