In our test system we have PHP 5.2.5 fcgi + XCache + MySQL 4.1.x installed. With this configuration we did an Apache benchmark:
ab -n100 -c10 http://shop-domain.com/index.php
The result was poor: only 2.41 requests per second.
Even XCache is a good OpCode cache for other systems (like TYPO3 or osCommerce) it really sucks on Magento and Zend framework.
So we replaced it with APC and changed the standard MySQL configuration for InnoDB:
innodb_buffer_pool_size = 32M
innodb_flush_log_at_trx_commit = 0
innodb_flush_method = O_DSYNC
innodb_log_buffer_size = 8M
innodb_log_file_size = 32M
apc.include_once_override = 1
And voilÃ : now we have nice 6.6 requests/sec - that’s an increase of 170% compared to our old configuration.
We’ll do some further testing and post our results in the forum.