One of the most powerful and complicated aspects of Apache is the mod_rewrite module. As its name implies, mod_rewrite provides the ability to rewrite URIs.
Although this feature does not necessarily represent a significant performance problem, for each rule that matches and each URI that must be rewritten, system resources are expended. The key is to try to avoid processing URIs too many times and to keep away from the URIs that you don't need to process.
One way of addressing this problem is to use the [L] option. This option tells Apache that it has reached the last rule it should apply to the given URI. That is, no further rules are processed. Unfortunately this is not as easy as it seems.
If the rewrite rule does in fact cause a redirection, the new URI is itself processed, and everything starts over again. In many cases you can avoid this with the use of re-write conditions (RewriteCond), so that if the URI matches a given condition, you won't need to process it further.
A related option is the [S] or skip flag. This flag will skip over a given number of rewrite rules. For example, if the URI is not a file (e.g., a directory) you can tell Apache to skip over rules that only apply to files. In other words, you don't avoid the rewrite rules completely, but you reduce the number you need to process.
In your development environment, you might want to have your files loaded with comments, but comment lines are detrimental on live servers. Comments that are structured properly can be removed easily with the use of shell scripts, which means you can comment your files for the testing phase and then remove the comments before you move files to the live server.
The Pareto principle (80:20 rule) applies to web server performance tuning. Implementing many of the concepts described in this article can increase your performance relatively quickly; however, to squeeze out the last bit of advantage, you probably need to spend a lot more time. Depending on the kind of server you run, your mileage will vary.
VMware bids for a stake in the container industry with a bold effort to integrate containers with its classic virtualization system.
3ROS attack tool lowers the technical bar so anyone can be an intruder.
Mozilla's latest browser offers powerful new privacy feature
If attackers are on your system, saving your passwords in a password vault is no protection.
Faulty hash algorithm persists, despite efforts by experts to raise awareness.
Powerful man-in-the-middle attack is now targeting online shopping.
Another high-profile coder says the kernel team needs a kinder, gentler culture.
Bug database has a bug of its own that could allow an intruder to create an unauthorized account.
Report focuses federal resources on achieving universal Internet access.
Leading browser makers say “no” to porous encryption algorithm