Are the Memcache servers on the same network as your NGINX server ? Perhaps they could be split off onto a separate network and add an additional NIC into the server. ----- Original Message -----
From: "Benjamin Fonze" <[email protected]> To: [email protected] Sent: Tuesday, 26 July, 2011 9:48:14 AM Subject: Re: Memcached not fast enough? Hi everyone, Thanks a lot for your replies. I'll try to comment upon your feedback. * Running several instances of Memcached sounds a bit silly indeed. I was testing a lot of different things and somehow it was working better than having one Memcached per server. That was a long time ago and I haven't tried to rollback to just one instance, nor do I know how this can impact (if any) performance. * The "issue" is that there is data that I can't cache into APC, I need it to be in one place and allow all the web servers to fetch it there. And the bottleneck of my application seems to be Memcache. At peak it can be about 20,000 HTTP requests per second. Each of them generating one Memcache call. If that call hangs for just a few milliseconds too much, then NGINX is very quickly overloaded as the workers are waiting for PHP to finish and Nginx simply maxout its workers. The LAN is 1Gbs. You are right regarding serializing. It makes it quite slower. I have also tried gzcompress to use less network bandwidth and that takes up a lot of CPU resource as well. In summary, there might not be any issue at all. But I thought Memcache should be faster to respond. If I log all the Memcache GET that my boxes are doing, I can see times ranging from 1ms up to 200ms or more. My sysadmin skills are limited, I'm a programmer. I'll try to have someone look at our hardware and see if that can be a network issue or something. Benja. On Mon, Jul 25, 2011 at 8:19 PM, Dustin < [email protected] > wrote: On Jul 25, 4:57 am, benjabcn < [email protected] > wrote: > Testing 1000 GETs. > Memcache Testing... > Value size : 149780 Bytes > Time: 13.78 seconds. What kind of network are you using here? That's a bit over 80Mbps.
