Wayfair went live with PHP in May 2011, after 9 years of running on classic ASP. Its customer-facing web sites were completely converted to PHP by April 2013.
Initially we had a classic LAMP-style stack, except with FreeBSD instead of Linux, Lighttpd instead of Apache, and Microsoft SQL Server instead of MySQL. Like a lot of sites, we had a Memcached to help with performance. This was fine for the size business we were at the time.
Since then we have had to scale up. We’re now a >$1B public company. We’re doing a lot of things with PHP that we have made available to the opensource community on github.com/wayfair. The thing that has required the most creativity, and is perhaps the most useful to others, whether or not they have a stack similar to ours, was getting connection pooling and proxying to work with our spiffy state-of-the-art caching infrastructure, and with SQL Server. This talk is a ‘how and why’ on all of that.