General Troubleshooting¶

Too Many Open Files¶

You can address a Too many open files error by increasing the operating system's file descriptor imit.

Too many open files errors happen when a process needs to open more files than it is allowed by the operating system. This number is controlled by the maximum number of file descriptors the process has.

File descriptors are used by your OS to store information about each open file and thus facilitate communication. The OS puts limits on how big file descriptor tables can get and therefore constrain how many concurrent requests the server can handle.

In UNIX-like operating systems, there are system-level and process-level file descriptor limits. The system-level file descriptor limit restricts how much your server can handle, but, because LiteSpeed Web Server only uses a small number of server processes to serve all clients, LSWS can also require a higher process-level file descriptor limit. Therefore, to use your server to its maximum potential, it is important to set both of these limits to a high enough value.

If the server is started by the root user when this limit is too low, the system will automatically try to adjust the limit based on server configurations. If the server was not started by the root user, this limit has to be manually adjusted with root privilege. You may want to put the following commands into your startup scripts in order to automatically set the limit after rebooting the machine.

Process-level file descriptor limits¶

Use the command ulimit -n to check current process-level file descriptor limit. The output may be something like 32768.

You can reset these limits by adding a number after the command, such as:

ulimit -n 3276800

Note: In Linux, non-root users can also use ulimit -n xxxx to change the process-level limit (at least in Kernel 2.4.x), but you need to add the following lines in /etc/security/limits.conf to give these users permission:

soft nofile 2048
hard nofile 8192

System-level file descriptor limits¶

Setting system-level file descriptor limits is different for each system.

=== Linux kernels Check the system-level limit for open files:

more /proc/sys/fs/file-max

If it looks low, increase the limit with:
```
echo 40000 > /proc/sys/fs/file-max
```

You may also need to increase `fs.nr_open`
```
echo "10000" >  /proc/sys/fs/nr_open
```

For kernel 2.2.x, you may also need to adjust the inode limit (the maximum number of files that can be stored in the file system):
```
echo 65535 > /proc/sys/fs/inode-max
```

=== Solaris 2.4+ Add the following lines in /etc/system:

To reset the hard file descriptor limit:
```
set rlim_fd_max = XXXX
```

To reset the soft file descriptor limit:
```
set rlim_fd_cur = XXXX
```

=== FreeBSD Add the following line in /boot/loader.conf:

set kern.maxfiles=XXXX