a web cache system base on nginx web server. faster and more efficient than squid. Features The large storage can save over 30,000,000 caches The self sort share memory hash index Use linux epoll, sendfile and aio to improve the performance Base on the fastest web server framework : nginx The high throughput and high concurrent volume of the cache request Without http headers cache Low cpu cost and low iowait Memory cache the hottest data use HAC Aio queue with lio_listio function http://www.ncache.org/

2. OVERVIEW F5 NGINX PROXY NCACHE BACKEND BACKEND BACKEND

3. STRUCTURE Be proxy hash index Init by Ngx master process when nginx is start on Ngx worker process Ngx worker process Disk Files Read / write by file system or raw dev Backend server Backend server Backend server Body filter Get the proxy content and save into the disk by aio

4. Logic Diagram Request Request Find cache in index found Not found Timeout? not yes Sendfile output Proxy backend Body filter Writev output Aiowrite fresh index

5. The self sort share mem hash index 2(5) 3(4) First floor of hash index List to solve the conflict of the hash Hash_malloc 1(6) Index[1]+2 = 7 1(6) 3(4) 2(7) Top:0 16777216 33554432 If arrived at the bottom of the share memory then ncache will return to the 16777216 point and find which can be reused

6. Record lock Mmap auto sync Mem index Sync file Worker process Worker process Read Write Worker process Do not need to lock any worker process or request cause wait not cause wait not cause wait

7. Performance between SQUID 1 First: cpu last: io Blue is ncache

8. Performance between SQUID 2 SQUID NCACHE