I want to lower number of open files on my VPS. With lsof I noticed that Apache constantly keeps access.log and error.log open for each domain hosted on server.
Is there a way to change this behaviour?
I want to lower number of open files on my VPS. With lsof I noticed that Apache constantly keeps access.log and error.log open for each domain hosted on server.
Is there a way to change this behaviour?
Many open files are usually not a problem. There's a system limit, which you can check using command sysctl fs.file-max
- on my CentOS 6 system with 4GB RAM it is 382299, which should be plenty, and on 256MB VM I started it was 23539, which can be somewhat too little. But you can easily increase this limit for example by adding to /etc/sysctl.conf
:
fs.file-max = 500000
And then running sysctl -p
or rebooting.
You can write a program which will open, write, close a log file every time data is received from stdin, and use it like this:
CustomLog "||open-write-close /var/log/httpd/access_log" common
but it won't be efficient. And it wan't be easy, as it would need to use async IO.
I've written a program for this in C:
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <limits.h>
int outfd;
int main(int argn, char* argv[])
{
if (argn != 2) {
fprintf(stderr, "Usage %s [output_file]\n", argv[0]);
return 1;
}
{
long stdinflags = fcntl(0,F_GETFL);
if ( stdinflags == -1 ) {
perror("fcntl: Can't read stdin status");
return 2;
}
if ( fcntl(0,F_SETFL,stdinflags|O_NONBLOCK) == -1 ) {
perror("fcntl: Can't set stdin to non-blocking mode");
return 2;
}
}
do {
#define BUFSIZE PIPE_BUF
char buf[BUFSIZE];
ssize_t bytesread = read(0, buf, BUFSIZE);
{
fd_set select_fdset;
FD_ZERO(&select_fdset);
FD_SET(0, &select_fdset);
if ( select(1, &select_fdset, NULL, NULL, NULL) == -1 ) {
if ( errno != EINTR ) {
perror("select");
return 2;
}
};
}
if ( bytesread==-1 ) {
perror("Can't read from stdin");
return 2;
}
if ( bytesread == 0 ) break;
outfd = open(argv[1],O_WRONLY|O_APPEND|O_CREAT);
if ( outfd < 0 ) {
fprintf(stderr, "Can't open file \"%s\": %s\n", argv[1], strerror(errno));
return 2;
}
do {
if ( write(outfd, buf, bytesread) == -1 ) {
fprintf(stderr, "Can't write to file \"%s\": %s\n", argv[1], strerror(errno));
return 2;
};
bytesread = read(0, buf, BUFSIZE);
if ( bytesread==-1 ) {
if ( errno==EAGAIN ) break;
perror("Can't read from stdin");
}
} while ( bytesread>0 );
if ( close(outfd) != 0) {
fprintf(stderr, "Can't close file \"%s\": %s\n", argv[1], strerror(errno));
return 2;
}
} while ( 1 );
return 0;
}
If you have really big number of vhosts with separate access log files, I suggest to log everything to one file (Yes, eliminate CustomLog in every vhost), and later use split-logfile application to separate them. You can join it with logresolve script, to resolve DNS names.
To split-logfile work, you need to set first column in CustomLog to ServerName.