We’ll cover some more advanced forms of improve the performance of linux.
Disabling than anything, or fiddling with the interface.
I separated the 3 things that I normally use to improve my servers, and virtual machines.
For those who do not know what is ramlog … can kill yourself now. Just kidding, read the rest. Then mate.
As the name says Rams – log means store the log in the ram, instead of pouring it on disk directly. How common is used by syslog.
Thus is avoided that there is always written to disk, which is a bottleneck of performance on any server. Exist only when the ramlog is restarted or stopped.
The use of ramlog, makes a big difference in performance
Ramlog – http://www.tremende.com/ramlog site you can find the installation tutorial for various distributions.
Hello, after a long time without writing, I finally found the time.
And in another tutorial, we’ll learn how discover open ports or closed on a server, computer …
For this task, we use the command nmap .
According to nmap’s own description, the application is:
Nmap (“Network Mapper”) is an open source tool for network exploration and security auditing. It was designed to track (Scan) large networks quickly yet works well with a single host (host). Nmap uses raw IP packets in (raw) on new ways to determine what hosts (hosts) are available on the net …
For more details you can find in http://nmap.org/ . I like to use nmap, but it does not mean that this is the only way to accomplish this task.
The simplest of commands, just run nmap to the server that you want to investigate
nmap test.com
nmap -s test.com
Very useful for network administrators
nmap 192.168.254.1 192.168.254.2 192.168.254.3
nmap 192.168.254.1-10Verifying a range using wildcard
nmap 192.168.254.*
Verifying a specific port
nmap -p [port] test.com
Verifying a range of ports
nmap -p 80-400 test.com
Again, this is not the only method of doing this scan. And you can find more about nmap the link: http://www.cyberciti.biz/networking/nmap-command-examples-tutorials/
utilizando o comando at linux
And alas! Let us understand more a Linux command, now the at . That also did not know until recently.
Imagine yourself in the following situation, you have to run a command now, so to come back from lunch (that’s damn silly example), but will only arrive at 14:30. and your boss wants the result of this command to 2 hours, or it will eat your … liver. Simple!! The command at will leave you with your … intact liver. Let’s practice, and stop bla bla.
The command behaves like a cron that will run, and then cease to exist. Much simpler than configuring a line in cron to run a command only once.
at practice
Assuming that the command that your boss wants to be shot tomorrow, and is the list of all users logged in at 14:00, by which it accesses a file on the network.
The command accepts multiple configuration variants of the date / time. For this example we use in this way
$ At 2pm tomorrow
at> who> / var / www / list_users.html
When you enter the command at it will open a “sub-terminal” at the for you to enter your command, in our case who> / var / www / list_users. html , to save at the command, use ctrl + d .
Tips command at linux
List commands (jobs) configured at the
Use command atq , it will list the work to be performed, for your user, if you are the root of all the users.
$ Atq
Delete commands (jobs) configured at the
Use command atrm , it will remove a specific job, you should specify the work to be removed. For example:
$ Atq
5 Fri May 17 13:30:00 2013 vinicius
6 Fri May 17 13:31:00 2013 vinicius
$ 5 atrm
Going deep in at
I advise to read the documentation at as there are many tips on the same
man at
For example:
Running a command in 3 days at 4 o’clock
at 4pm + 3 days
Running a command on a specific day (18.10.2013) at 4 o’clock in the morning
Observer this example, the date is in standard MMDDCCYY
at 4am 10,182,013
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