Today my DBA reported that the server she was working on was spitting out “too many open files” errors and no new processes could be started.

This is a common problem with DB servers with heavy transactions. In my environment there are 6 DB instances running on the server. No quite the optimized setup I would say.

The fix was to increase the total file descriptors kernel parameter count in the /etc/sysctl.conf file. I doubled my limit from 8192 to 16384.

The walk through,

  1. Find out what the current open file descriptor limit is.

    ~# more /proc/sys/fs/file-max

    ~# 8192


~# sysctl -a | grep fs.file-max

~# fs.file-max = 8192
  1. View how many open file descriptors are currently being used.

    ~# more /proc/sys/fs/file-nr

    ~# 8191

  2. View how many files are open. The number returned might defer as 1 file descriptor can have multiple open files attached to it.

    ~# lsof | wc -l

    ~# 10325

  3. Edit the kernel paramneter file /etc/sysctl.conf and add line “fs.file-max=[new value]” to it.

    ~# vi /etc/sysctl.conf

    fs.file-max = 331287

  4. Apply the changes.

    ~# sysctl -p ~# fs.file-max = 331287

Problem fixed.