Configuration changes

I made some modifications to my nginx configuration this weekend to improve performance and clear up some bugs.

upstream backend {
    server fail_timeout=120s;

server {
    listen 80;

    access_log /var/log/nginx/;

    gzip on;
    gzip_disable msie6;
    gzip_static on;
    gzip_comp_level 9;
    gzip_proxied any;
    gzip_types text/plain text/css application/x-javascript text/xml
    application/xml application/xml+rss text/javascript;

   location / {
        root /var/www/;

        set $wordpress_logged_in "";
        set $comment_author_email "";
        set $comment_author "";

        if ($http_cookie ~* "wordpress_logged_in_[^=]*=([^%]+)%7C") {
             set $wordpress_logged_in wordpress_logged_in_$1;

        if ($http_cookie ~* "comment_author_email_[^=]*=([^;]+)(;|$)") {
            set $comment_author_email comment_author_email_$1;

        if ($http_cookie ~* "comment_author_[^=]*=([^;]+)(;|$)") {
            set $comment_author comment_author_$1;

        set $my_cache_key "$scheme://$host$uri$is_args$args$wordpress_logged_in$comment_author_email$comment_author";

        client_max_body_size 8m;

        proxy_redirect off;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_pass_header Set-Cookie;
        proxy_cache cache;
        proxy_cache_key $my_cache_key;
        proxy_cache_valid 200 302 60m;
        proxy_cache_valid 404 1m;
        proxy_pass http://backend;

    location ~* .(jpg|png|gif|jpeg|js|css …