Server performance worsened after a hardware upgrade: how should I reconfigure the server?

Question

I'm running a site on an Ubuntu/Apache/Django/PostgreSQL stack. We upgraded our server recently from 1 processor with 2 Gb total RAM (with 0.5 Gb of that RAM assigned to memcached) to a new server that has 2 processors with 4 Gb total RAM (with 2 Gb of that RAM assigned to memcached). However, when I looked at Google Webmaster Tools, I found out that the average page speed has worsened from 5 seconds to 15 seconds.

Why would performance get worse with a hardware upgrade? What should I check and tune? Is this more likely to be a problem with memcached, Apache, Django, or PostgreSQL?

It will depend on the load that's on your website as well, when you are testing. — Lucas Kauffman, Mar 15 '12 at 08:32
The load is basicall the same before upgrade and after it. The traffic is about 4 000 unique visitors in average per day. — Иван, Mar 15 '12 at 08:43
I am sorry, your comment is not clear, what measurements do you mean? — Иван, Mar 15 '12 at 11:07

score 0 · Accepted Answer · answered Mar 18 '12 at 23:42

Profile your setup. Check for bottlenecks. Maybe Postgres is out of IO, or you should give it more RAM instead of memcached. Use atop it collects "historical" stats and is pretty thorough.

Then do client side benchmarking, because it might be that the site is taking 10+ seconds because of too many HTTP connections, too many small images, CSS or JS files. Use Y! Slow or Google Page Speed .. or just plain and simple FireBug.

Also, you might get better results by using NGiNX for serving static content before the whole Apache/Django thing. Or drop Apache completely and use this ( code.djangoproject.com/wiki/DjangoAndNginx ) and something like runit to keep the workers alive.

Server performance worsened after a hardware upgrade: how should I reconfigure the server?

1 Answers1