100 Day Review Of LiteSpeed (Apache Drop-in Replacement)

(This is the first review I've ever written for practically anything so please bear with me. I feel the need to share my experience to try to help others after all the great advice and info I've received around here.)

If you've done everything you think you can do to improve the responsiveness of your websites like add a mysql cache, PHP opcode cache and various other tweaks, I discovered there is still one more easy thing you can do for a big improvement: replace Apache with LiteSpeed. It's way too easy not to try it and you can leave Apache completely intact to go back to at a moment's notice if you so desire.

I call LiteSpeed a "drop-in" replacement because it uses all my httpd.conf and .htaccess settings without modification. This was critical for me as my sites have some very complex rewrite rules. Other solutions like LightHttpd require extensive work to make changes if you use fancy mod-rewrite rules. LiteSpeed does not need any fiddling. LiteSpeed just adds it's own clean little web interface so you can tweak if you want to, but I didn't really have to change anything. Last but not least, LiteSpeed gets along with Cpanel and DirectAdmin without any conflicts. LiteSpeed's so compatible I can literally do this on my server and the visitors don't even notice the difference (except speed of course!)

service httpd stop
service lsws start
(and visa versa)

I discovered LiteSpeed after reading that the main WordPress.com site had switched to it and had great success (they have a quarter million registered bloggers and of course many millions more daily readers).

The main reason I tried LiteSpeed is because it's roughly twice as efficient in memory use and performance than Apache 1.3 & 2. It runs PHP up to 50% faster than Apache and static files get served several times faster (faster than thttpd & lighthttpd). So this means you can either double the number of active connections you currently max out at now, or make a regular website respond nearly twice as fast, or under heavy loads still respond within a reasonable amount of time when Apache would be completely unresponsive.

The last situation was exactly what I was hoping for and LiteSpeed helped me keep my sanity on a bad VPS node.

Basically a couple months into owning my first VPS (after many years of shared-hosting experience) I started to realise many of the industry promises about VPS are an outright lie. You are far from isolated from your neighbours. Any disk load created by bad neighbours, mysql abuse or otherwise, will directly affect you and you are powerless to stop it. It's the most poorly regulated resource on any VPS node and it can be made worse by slack, ignorant or inexperienced hosts who do things like move accounts during busy periods onto and off a node at the root level which ties up the entire node for an hour or more. Under Apache, I was getting timeouts during peak visitor times and that was very upsetting.

On top of my VPS neighbour troubles, no matter how I fiddled with Apache's settings (with all the helpful guides around here) I could not make it comfortably fit within the guaranteed memory limit of my VPS with Cpanel, which I really wanted to keep as it's much easier for my end-users. Switching to LiteSpeed caused a radical drop in memory use. I've seen nearly 1000 people online within a one minute period on one of my sites and it still fit comfortably within my memory limits and stayed extremely responsive.

I've discovered another plus to LiteSpeed along the way that no-one else seems to mention. It's the only server software that "out of the box" seems to serve web compressed (gzipped) pages properly as chunked output. This means a visitor will start to see the page immediately as soon as the first part is sent vs. on Apache, mod_gzip actually de-chunks all the output, waits for it to finish, then compresses, then sends.

Mod_deflate on Apache 2.0 was supposed to fix this but it usually doesn't work properly and I've never gotten 2.0 to do compressed+chunked output on my sites without alot of fiddling and help from PHP. It also doesn't seem as smooth as LiteSpeed's output which gives you that "silky" watch-the-webpage render effect that's mentally rewarding to visitors.

On the downside, there is one reason you wouldn't use LiteSpeed - if you use highly customised Apache mods. LiteSpeed cannot support custom mod's and their directives. It does have a lot built in however that Apache does not, so you may way to examine if you can accomplish what you are trying to do another way.

I started with LiteSpeed 3.1 and when I found an incompatibility with an obscure Apache feature (ie. ErrorDocument's as plain text output: ErrorDocument 404 "Not Found" was not supported) they fixed it for me in a day or so after I reported it on their forum. The same for PHP support of "Apache_Response_Headers". Note I am not even a commercial customer! They are now up to 3.2 which has a few other fixes.

The free version of LiteSpeed has a limit of 150 simultaneous connections (plus the linux stack of 200 more which will backlog). I've never seen that limit hit. It's so intelligent about closing connections as needed that it's not an issue for me. Perhaps on a dedicated server with many virtual hosts this will be a problem. Up to version 3.1.1 that was the only limitation, however unfortunately in 3.2 they have decided to also limit virtual hosts to "5", so that's something else you'll have to consider if you want the free version, otherwise the commercial version has a free trial and money back guarantee.

Some people were upset with me that I wouldn't name my VPS host when I was constantly complaining of troubles but that's just my style when I have nothing nice to say still have to do business with them, so don't name names. But when I have something nice to say about a company, I like to speak up. So I heartily recommend LiteSpeed and hope other people give it a try - especially if you are on my VPS node ;-)