A naive question regarding Linux system administration, but, still, I HAVE to ask

Hello guys !

(EDIT : I now realize my post was too poorly written, I apologize for this. I do not care about optimizing performance and tuning the system. I do not seek a craftman’s approach. I really am focused on a bottleneck scanning tool, and let the admin do what he wants with the output. Please see the replies I made to the comments at the bottom of this post…)

The rest of this post is about managing a linux server’s resources, so if that doesn’t arouse you (how could it not ?!?), or if that doesn’t interest you, you should just skip this post ^^

Since I gave up on shared hosting and moved on to dedicated hosting, I learned a lot. Both in terms of security and in terms of server managing.
And there’s something that has been troubling me ever since.

When something works too slowly, it’s possible that the problem doesn’t lie in the server’s hardware (CPU, RAM, Disks), it may lie in the server’s configuration. Those evil bottlenecks.
For example, how the limits to Mysql are configured, in terms of open processes, or cache, in number of simultaneously open files… Or for PHP’s handler… Or for the memory limits… Or how Apache’s limits are set, between too generous and too restrictive…

This calls for testing and fixing.
At least, with Mysql (possibly the most common bottleneck), there are various tools like Mysqltuner.
However, what if we don’t want to make things work better, but we want to know if something simply is already at the maximum, and who cares – for the moment – for what reason ?

See… why isn’t there any system-wide checker for bottomnecks ?

A program that would, most simply,
1) COMPARE
. the current state of system values
(read from other monitoring commands)
. versus the upper limit on the system for these values
(mentioned in config files or defined by software defaults)
2) and PRODUCE A REPORT

Once that report is done, it’s all in the admin’s hands.
With that report in hand, he may use it to optimize performance, or use it to fix a problem, or use it to find where a hard to tackle problem finds its origin. I mean : really, who cares, the main point is to produce this report, there’s an infinity of usage scenarios for such a tool.

A program like that would tell us, for instance, let’s imagine…
. “you’re within 99% of the maximum value of 1024 for open-files-limit as defined in /etc/mysql/my.cnf”
. “you’re within 98% of your system’s default value of 250 for MaxClients , which may be adjusted in /etc/apache2/apache2.conf”
. “in the 5 minutes the monitoring lasted you reached 41 times the max value of 1024 for mysql soft nofile, which is a default value but may be adjusted in in /etc/security/limits.conf…” (errr, or adjusted in /etc/mysql/my.cnf, I have doubts now ^^;;)

That would NOT be a tuner. Just a report.
Once again : let us let the admin deal with the results. It’s his business why he uses it and what he does of the results.

This would be only a program that reads what are, system-wide, the maximum values for the system settings (either by default, or, when specified, as mentioned in configuration files), and that monitors the system for a few minutes, to report which of these values are hitting or stuck to their maximum. Reporting the bottlenecks.

Sure, there are tons of elements to scan, so maybe it could be limited to a typical webserver’s profile, Apache/Sql/Php. Still a ton of variables, but now a finite and determined number.

As far as I am concerned, this would be SUPER DUPER useful.

I could give you a personal example…
I don’t know if you noticed it, yesterday Hentairules was offline during two hours ?
That was because I had a bug (something broke, after which, chaaarge!, domino effect !) and I didn’t know which system value(s) had to be adjusted to allow the system to “calm down”, basically. The Mysql engine remained fucked up even after a reboot (my most joyful discovery of the year in server administration : sometimes a reboot doesn’t fix shit at all even if nothing altered the system’s settings, yay ! I’m so glad to know this may not be enough !), and to fix it, mysql required to be allowed to deal with more stuff than before to fix itself… except that I didn’t know WHAT in blazing hell, needed to be changed, I didn’t even understand it was a setting for Mysql that required changing. It took a lot of time to find what had to be updated, I spent hours parsing error logs, googling stuff, and running dozens and dozens and dozens of command lines
And yet, if I had had a bottleneck-checker utility, it would have only taken a minute to spare me many hours, I would have had my report that there was this and that desperately stuck to the maximum, it would have massively eased up the whole system fixing.

Do you see what I mean ?

And yet, a program like that doesn’t exist.

There must be hundreds of good reasons for this not to exist. I wish I could name one

What are your thoughs, about it ?
Does such a program actually exist ? (If you say “yes” and provide me a link, I may have an orgasm, fair warning)
Is it impossible because of the differences between distros ? (To this, I would object there are only few differences between major distros regarding where the system settings are stored, and at worst we could document it in the script’s config)
Any other thoughts ?

(Edit : you’re reading a second version of my post, I brought lots of changes. The first version looked focused on optimizing and monitoring, while this is NOT my purpose at all. I am really focused on bottlenecks searching and reporting. Keep that in mind while reading the comments ^^)