Efficient delivery of maintenance page from Varnish

I've configured an varnish instance to deliver a custom maintainance page when it can't reach a backend server instead of the default guru meditation page. The subroutine that delivers the maintainance page looks similar to this:

sub deliver_maintainance_page
{

   set obj.http.Content-Type = "text/html; charset=utf-8";

   synthetic {" 
     <!DOCTYPE html>
     <html dir="ltr">
        ...
     </html>
   "};

   return(deliver);
}

The missing html (the dots) also includes image and font resources embedded using the data uri scheme (http://en.wikipedia.org/wiki/Data_URI_scheme). The total weight of the document is ~208 kb.

Is this really the best way to deliver a custom maintainance page ?

Solution

I do two things for my custom maintenance pages. I use a CDN or image host (see Amazon S3, CloudFlare, Akamai, Imgur, etc) to host all images on the page (for big sites I recommend a CDN, CloudFlare has a free plan). Then I move the HTML for the page into an external file and use std.fileread which is built into Varnish. E.g:

import std;

sub deliver_maintainance_page
{
   set obj.http.Content-Type = "text/html; charset=utf-8";

   synthetic std.fileread("/var/www/errors/503.html");

   return(deliver);
}

This cleans up your VCL file and reduces page weight (no more inline images).