Never mind the PHP, it's a topic I don't want to discuss :) About the changes - the only change that made this impact was changing the hash distribution method. We are currently using the new memcache instances, but with the standard, naive method and there are no negative effects on the load of the web nodes. The moment we switch to the consistent method the load jumps.
On 27 Фев, 16:53, Brian Moon <[email protected]> wrote: > On 2/27/09 8:50 AM, Pavel Aleksandrov wrote: > > > > > Hello, I am working for a big web site. We have around 9000 hits/s on > > our MySQL replication trees and 500 000 unique visitors each day, just > > to give a clue about the load we are experiencing. We run on MySQL, > > Apache2, Gentoo, PHP 4 + PECL Memcache module. We've been using a > > single 12G memcached instance for speeding up things (we've reached > > the point where we can't solely rely on our DB). Using a single > > instance is not what memcached is meant for, so we decided to scale > > things up a bit, so we added 12 more instances, 2G each (32 bit > > servers, 4 instances per server, 3 servers). Then we switched from the > > "standard" (naive) method of hash distribution to the "consistent" > > method. > > > What happened was that the load on our web nodes (we have 3 of them) > > went up about 3 times the usual. I'm guessing it's the new hash > > distribution method that's doing this. Am I missing something or using > > this method is always so CPU intensive? Do we have another choice or > > we should invest in more web nodes, to distribute the new load if we > > decide to stick to the consistent hashing algorithm? > > Are you really using PHP4? Not related just shocked. > > Did you make all these changes at once? > > -- > > Brian.
