how to increase the max open files of nginx master process
 

Hi All,

I know there is a config called: worker_rlimit_nofile which could change the max open files of nginx worker, but how to increase the master's ?

# ulimit -a
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 773092
max locked memory (kbytes, -l) 64
max memory size (kbytes, -m) unlimited
open files (-n) 65535
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 8192
cpu time (seconds, -t) unlimited
max user processes (-u) 773092
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited

nginx version:
/usr/local/nginx/sbin/nginx -v
nginx version: nginx/1.4.4

OS:
14.04.3 LTS, Trusty Tahr

worker config:
worker_rlimit_nofile 20480;

/proc/8389/limits:
Max open files 1024 4096 files

8389 is the master process id.

Nginx is not managed by Systemd, systemV instead.

Thank you in advance

You really don't need to.

The task the master is doing is to receive connection requests - and then pass the connection to a worker.

The normal number of requests will be 0, and 1 when a connection request comes in. It only takes a few microseconds to pass that connection to a worker. The only other files open would be stdout/stderr and those would be redirected to a log file.

Additional requests will be queued for processing - but the master process can only handle one at a time.

The purpose for having many simultaneous connections for a worker is via multi-threading. There can be MANY threads active - but there would be only one connection to the client - and only a few more used to access data. The aggregate for the workers could be a large number (assuming multi-threaded). If each thread is an independent process, then having a huge number of open files would be a bit of a waste.

The general reason for 1024 open files as a limit is that it is also the limit of file descriptors the select system call can support. Epoll can handle more - but usualy the only thing that needs that many files open at a time would be a database server, not a web server.

@ Jpllard

Thank you for your comment. But I actually configured my nginx to use epoll, so I just want to know why the max open files is still 1024 and how could I increase it.

Thanks