Parallels

Symptoms

RPM packages are compiled by vendors with too small (1024) a number of file descriptors, and it might cause the following messages to appear in the /var/log/httpd/error_log:

    Segmentation fault (11)

    [warn] make_sock: problem listening on port 443, file descriptor (1068) larger than FD_SETSIZE (1024)

    Unable to open logs

    Too many open files

This is a common Apache issue on servers with many Virtual Hosts configured. See this article for more information: http://httpd.apache.org/docs/2.0/misc/descriptors.html.

Resolution

NOTE: Since Plesk 8.2.0, up to 900 domains can be hosted on the OS vendor Apache build without the system packages recompilation described in this article. If the Piped Logs feature is enabled on the Plesk server,  see 2066.

NOTE: This article is for Linux operation systems that have RPM packages structure, such as RHEL, Fedora, CentOS, SUsE.
For details on the Debian system, please see this article.
For details on the FreeBSD system, please see this article.

NOTE: Plesk requires, closely depends on, and uses many server applications which are not actually part of Plesk software. For example, the apache web server, mysql server, php module and binaries, and many others are not compiled by Parallels and not provided by Parallels, but standard system RPM packages from the operating system vendor are used by Plesk 'as is'. This allows the administrator to upgrade and recompile such packages with the desired options. This article is written to help administrators of Plesk configure their OS and system packages that are not included in the Plesk distributive to use with a large number of hosted domains.

You need to recompile related applications and libraries such as openssl, apache, imap, PHP, etc, from source RPMs with increased FD_SETSIZE value. Please follow these steps:

Make sure that the system allows you to open enough files:

If fs.file-max is quite small (several thousand or so), it should be changed by adding the following lines to /etc/sysctl.conf:

fs.file-max = 131072

and running the shell command:


NOTE: if you are running Virtuozzo, you have to adjust fs.file-max on the hardware node and it will be applied to all VEs.

You should have glibc-kernheaders and glibc-headers packages installed. They can be taken from the operating system distributive CD or from your operating system's download sites. Edit the __FD_SETSIZE value in the typesizes.h and posix_types.h files that can be found with:

and set it as:

#define __FD_SETSIZE 65536

Download the following source RPMs that can be found on your operating system's download sites or similar places. You may use RPM search engines such as http://rpm.pbone.net or http://rpmfind.net:

openssl-*.src.rpm
httpd-*.src.rpm
imap-*.src.rpm
php-*.src.rpm
libc-client-devel-*.src.rpm (if such RPM is installed)
curl-*.src.rpm

Recompile openssl first. For example:

Install compiled openssl RPM with the following command line:

Repeat the same actions for cURL.

Recompile and install apache:

Recompile and install libc-client library which is provided by imap or libc-client-devel packages (depends on OS) . You have to recompile one that is installed in the system. For example:

or

Recompile and install PHP. For example:

Add a `ulimit -n 65536` command to /etc/rc.d/init.d/httpd and /usr/sbin/apachectl apache startup scripts before other commands.

Replace /usr/sbin/suexec with a Plesk one:

Use the following commands for Plesk versions earlier then 7.5: