This is a canonical question about capacity planning for web sites.
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What are some recommended tools and methods of capacity planning for web sites and web-applications?
Please feel free to describe different tools and techniques for different web-servers, frameworks, etc., as well as best-practices that apply to web servers in general.
I have created a new EC2 instance. It got assigned the default security group. I want to change that security group. How?
Is there an equivalent of MySQL's SHOW CREATE TABLE in Postgres? Is this possible? If not what is the next best solution?
I need the statement because I use it to create the table on an remote server (over WCF).
I don't want anyone to be able to detect that I'm using NGINX or even Ubuntu from the internet. There are tools out there (such as BuiltWith) which scan servers to detect what tools they're using. Also, some cracking tools might help with deteting. What's the best / closest to that I can get to hiding all this info from the outside?
I have scheduled a cron job to run every minute but sometimes the script takes more than a minute to finish and I don't want the jobs to start "stacking up" over each other. I guess this is a concurrency problem - i.e. the script execution needs to be mutually exclusive.
To solve the problem I made the script look for the existence of a particular file ("lockfile.txt") and exit if it exists or touch it if it doesn't. But this is a pretty lousy semaphore! Is there a best practice that I should know about? Should I have written a daemon instead?