It is important to note the worker_rlimit_nofile value should be greater or equal to worker_connections. For example, OpenBSD has a really low open file limit of 128 files for a normal user; i. This directive simply allows Nginx to try to set “ulimit -n value” when nginx starts. You will want to set this directive to at least 1024 to avoid errors. When you set this directive you will not need to set a separate “ulimit -n ‘value’ ” in the OS. You will also want to make sure that if you are keeping connections open for a long time with keepalive statements to watch this value. Each open connection is a used open file descriptor and thus counts against your “ulimit -n” value. If your open file limit is too low for the amount of connections nginx is making you will see the error, “Too many open files” in the error log. Default value (the ulimit -n value) will be overridden. In the case of Nginx this translates to the amount of open network connections to remote clients in addition to proxied backend connections. Understand that the open file limit is really regulated by the operating system. If worker_rlimit_nofile is not specified, your default ulimit -n number for the user who is running nginx will take effect. Worker_rlimit_nofile : is the maximum number file descriptors (ulimit -n) that can be opened by EACH worker_processes.
However, between colleagues, random folks on irc, and personal experience, I’ve seen a plethora of often subtle issues, gotchas and insights, which today I’d like to share. Hence my continued use and recommendation. This is a crosspost of an article I wrote on the raintank. All three are fantastic tools and solve very real problems. Io blog
For several years I’ve worked with Graphite, Grafana and statsd on a daily basis and have been participating in the community.
My UP X9SRL-F E5-1620 + WIN2012 + 4×16 Gb DDR3 1600 ECC REG KVR16R11D4/16 managed in STREAM only ~35,6 – 38,3 Gb/s [http://i. SiSoftware Sandra Business 2013 similar results ~ 37 Gb/s [http://i. Jpg], so i little bit pissed, expected to hit half of what hp DP e5-2600 xeons shows ~ 87,7 Gb/s according to HP documents.
BoringSSL is Google’s modified version of OpenSSL v1. For example, Google removed the dependency of the heartbeat code which led to the HeartBleed exploit as well as much of the legacy OpenSSL code. 2 including hundreds of Google’s patches minus much of the code bloat from OpenSSL.
The advantage of a low worker_process count is fast reaction times when a client connects. When a client issues a request there is some serial contention when Nginx assigns a processes to fulfilling a request. The last free core is left to be used by the OS and interrupts for the network interface. When you multiply workers, three(3) in this case, against worker_processes you get to total amount of client connections accepted by nginx. Setup the worker_processes to as low a number as you feel can support the maximum number of concurrent users connecting to your site. We can set worker_process to as little as 25 since workers times worker_processes would equal 75. By keeping worker_processes low you gain fast reaction speed. Lets say our webserver will never expect to receive more then 50 concurrent users at any one time. A four(4) core machine would have three(3) workers. Workers and worker_processes: ideally you want to setup nginx to use one(1) less worker then you have physical cores in your machine.
The first test will show us how fast our system can sign our ssl certificate during a handshake and how many ssl clients we can handshake with per second. A handshake is the action of the client and server opening up an encrypted connection between each other and negotiating with the site’s SSL certificate. The common size of a SSL certificate is 1024, 2048 or 4096 bits. For example we sign calomel. So, when a client connects to our site they must negotiate with us with a rsa 4096 bit certificate. Org with a rsa 4096 bit key.
Once you’ve written a command that you feel approximates the type of workload you perform on your PC, you can stress test several drives and see which offers the best performance. Using these options, you can tweak the benchmark command to see how your disk performs under varying loads.
The only purpose of this machine is to support the main web server by delivering buttons, favicons, signature images and such. X system we setup to serve out static images for a web site. Here is an example of a FreeBSD 9. We found that the majority of calls were made for these support objects and it was desired to split this function off to another box. There are a few security tweaks to the system, but mainly it is a default install with _no_ /boot/loader. Many sites split off their static data like Google’s gstatic.
Being hit by a big DDOS is not something you can just flip a switch and hold off unless you are ready for it and understand it. You need to plan for worst case scenarios and understand what steps you are going to take to stop an attack. Setup your servers securely, limit access to your services to sane values, try to use caching as much as possible and understand what each anti-dos mitigating step will accomplish. You may find you can hold off the script kiddies with your normal web server, a larger DOS with a reverse proxy cluster and a large DDOS with a distributed reverse proxy constellation.
This is a basic webserver running on port 80 (http) serving out web pages. On an AMD64 3GHz machine this config will easily serve out thousands of pages a minute. Though we have added quite a few security checks, this is as basic a server as you can get.
Just like stated before, this value can be lowered to as little as 5 seconds to help mitigate attacks like the Slowloris DoS attack explained lower on this page. Client_header_timeout is the timeout reading the title of the request of the client. If after this time the client send nothing, nginx returns error “Request time out” (408).
For example, if we say X or Y the format is “[X|Y]”. The following ssl_cipher list shows ECDHE-ECDSA-CHACHA20-POLY1305 and ECDHE-ECDSA-AES128-GCM-SHA256 and ECDHE-ECDSA-AES256-GCM-SHA384 as equal-preference high end ciphers just as Google explained. This is the standard regular expression format meaning “OR”. The ciphers which are considered to be of similar strength are put into square brackets separated by a pipe.