Hi,

I'm using nginx 1.8.0 on Ubuntu 14.04 LTS.

# nginx -V

nginx version: nginx/1.8.0
built with OpenSSL 1.0.1f 6 Jan 2014
TLS SNI support enabled

configure arguments: --with-cc-opt='-g -O2 -fPIE -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -D_FORTIFY_SOURCE=2 -mtune=corei7-avx -march=corei7' --with-ld-opt='-Wl,-Bsymbolic-functions -fPIE -pie -Wl,-z,relro -Wl,-z,now -mtune=corei7-avx -march=corei7' --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --lock-path=/var/lock/nginx.lock --pid-path=/run/nginx.pid --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp-path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-debug --with-pcre-jit --with-file-aio --with-http_ssl_module --with-http_stub_status_module --with-http_realip_module --with-http_auth_request_module --with-http_addition_module --with-http_geoip_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_image_filter_module --with-http_perl_module --with-http_secure_link_module --add-module=/opt/rebuildnginx/nginx-1.8.0/debian/modules/headers-more-nginx-module --add-module=/opt/rebuildnginx/nginx-1.8.0/debian/modules/nginx-auth-pam --add-module=/opt/rebuildnginx/nginx-1.8.0/debian/modules/nginx-cache-purge --add-module=/opt/rebuildnginx/nginx-1.8.0/debian/modules/nginx-development-kit --add-module=/opt/rebuildnginx/nginx-1.8.0/debian/modules/nginx-echo --add-module=/opt/rebuildnginx/nginx-1.8.0/debian/modules/ngx-fancyindex --add-module=/opt/rebuildnginx/nginx-1.8.0/debian/modules/nginx-lua --add-module=/opt/rebuildnginx/nginx-1.8.0/debian/modules/nginx-upstream-fair --add-module=/opt/rebuildnginx/nginx-1.8.0/debian/modules/set-misc-nginx-module

I have noticed that when I restart nginx (using restart or just simple stop and then start) the cache is not invalidated as it used to be.
After each restart I get HIT for all pages that were valid in cache before the restart.
Did anyone else noticed this behavior ? If yes, how did you fix it?