On Mon, 25 Mar 2002, Hans Juergen von Lengerke wrote: > We are currently using squid set up as a reverse proxy to accelerate > several heavy backends (mod_perl, etc) and to protect them from slow > client connections. > > I am looking into replacing the squid with apache+mod_proxy. Why? > Because ultimately I'd like to be able to cluster the frontend using > mod_backhand + wackamole. The primary reason for clustering isn't for > load-balancing (yet) but for failover handling. So, ideally, one machine > should be enough to serve the whole server load. > > Speaking of load, the squid (2.3.STABLE1) is currently doing up to 80 > requests per second at a cache hit ratio of around 72%. This is on one > box, a Dual 500MHz Pentium III with 1GB RAM. Average object size is 6KB. > 200/304 ratio is around 5/3. > > Now, I've tried to replace the squid with apache+mod_proxy (1.3.11) and > the frontend very quickly came to a standstill. I set MaxClients to 256 > but all slots filled up fast. I upped MaxClients to 512 (recompiled with > patched httpd.h) but the result was the same. All slots were occupied in > no time and the server ground to a halt. > > Now I'm left with two choices: give up or try harder :-) > > Before I decide for one of them I thought I'd ask on the lists (sorry > for the x-post) to see if the above numbers (80 Hits/Second) are in fact > feasible with apache/mod_proxy on one box. Are there any benchmarks > around? Does someone have a similar setup and how many requests can they > serve? Should I up MaxClients any further? Will I get better results > using a newer version of apache? Or should I give up and stick with > squid?
Apache can easy handle 80r/s on Ethernet or localhost connection. But if connections are slow (i.e. modem users) and responses are big enough then you can reach MaxClients. As far as I know 80r/s rate requires about 400-600 Apache with 20-40K responses. If your responses are bigger then more Apaches you need. You can increase MaxClients until your swap is free. On 1G you can run about 1000-2000 plain Apaches. But if you plan to use mod_proxy to proxy backend I think you should use mod_accel. Igor Sysoev
