Open Files Limit

Riak KV can accumulate a large number of open file handles during operation. The creation of numerous data files is normal, and the backend performs periodic merges of data file collections to avoid accumulating file handles.

To accomodate this you should increase the open files limit on your system. We recommend setting a soft limit of 65536 and a hard limit of 200000.

Changing Limit For Current Session

Most operating systems can change the open-files limit for the current shell session using the ulimit -n command:

ulimit -n 200000

Debian & Ubuntu

Start by checking the current open file limit values with:

ulimit -Hn # Hard limit
ulimit -Sn # Soft limit

If you installed Riak KV from a binary package, you will need to the add the following settings to the /etc/security/limits.conf file for the riak user:

riak soft nofile 65536
riak hard nofile 200000

If you use initialization scripts to start Riak KV, you can create a /etc/default/riak file and add the following to specify a limit:

ulimit -n 200000

This file is automatically sourced from the initialization script, and the Riak KV process will inherit this setting. Since initialization scripts are always run as the root user, there’s no need to set limits in /etc/security/limits.conf.

Enable PAM-Based Limits for Debian & Ubuntu

You can enable PAM-based user limits so that non-root users, such as the riak user, may specify a higher value for maximum open files.

For example, follow these steps to enable PAM-based limits for all users to allow a maximum of 200000 open files.

1. Edit /etc/pam.d/common-session and add the following line:

session    required   pam_limits.so

2. Save and close the file. If /etc/pam.d/common-session-noninteractive exists, append the same line as above.

3. Edit /etc/security/limits.conf and append the following lines to the file:

* soft nofile 65536
* hard nofile 200000

4. Save and close the file.

5. (Optional) If you will be accessing the Riak KV nodes via secure shell (SSH), you should also edit /etc/ssh/sshd_config and uncomment the following line:

#UseLogin no

And set its value to yes as shown here:

UseLogin yes

6. Restart the machine so the limits take effect and verify that the new limits are set with the following command:

ulimit -a

CentOS & Red Hat

Start by checking the current open file limit values with:

ulimit -Hn # Hard limit
ulimit -Sn # Soft limit

If you installed Riak KV from a binary package, you will need to the add the following settings to the /etc/security/limits.conf file for the riak user:

riak soft nofile 65536
riak hard nofile 200000

If you use initialization scripts to start Riak KV, you can create a /etc/default/riak file and add the following to specify a limit:

ulimit -n 200000

This file is automatically sourced from the initialization script, and the Riak KV process will inherit this setting. Since initialization scripts are always run as the root user, there’s no need to set limits in /etc/security/limits.conf.

Enable PAM-Based Limits for CentOS and Red Hat

You can enable PAM-based user limits so that non-root users, such as the riak user, may specify a higher value for maximum open files.

For example, follow these steps to enable PAM-based limits for all users to allow a maximum of 200000 open files.

1. Edit /etc/pam.d/login and add the following line:

session    required   pam_limits.so

2. Save and close /etc/pam.d/login

3. Edit /etc/security/limits.conf and append the following lines to the file:

* soft nofile 65536
* hard nofile 200000

4. Save and close the /etc/security/limits.conf file.

5. Restart the machine so that the limits to take effect and verify that the new limits are set with the following command:

ulimit -a

Solaris

To increase the open file limit on Solaris, add the following line to the /etc/system file:

set rlim_fd_max=200000

Reference

Mac OS X El Capitan

Start by checking the current open file limit values with:

launchctl limit maxfiles

The response should look something like this:

maxfiles    65536          65536

The first column is the soft limit and the last column is the hard limit.

To change the open files limits on Mac OS X El Capitan, perform the following steps:

1. Add the following line to your .bash_profile or analogous file:

ulimit -n 65536 200000

2. Save and close the file. Next open /etc/sysctl.conf (or create it if it doesn’t already exist) and add the following settings:

kern.maxfiles=200000
kern.maxfilesperproc=200000

4. Restart your computer and enter ulimit -n into your terminal. If your system is configured correctly, you should see that maxfiles has been set to 200000.

Mac OS X Yosemite

Start by checking the current open file limit values with:

launchctl limit maxfiles

The response should look something like this:

maxfiles    65536          65536

The first column is the soft limit and the last column is the hard limit.

To change the open files limits on Mac OS X Yosemite, perform these steps:

1. Add the following line to your .bash_profile or analogous file:

ulimit -n 65536 200000

2. Save and close the file. Next edit the /etc/launchd.conf file and add:

limit maxfiles 200000

3. Save and close the file.

4. After restarting, verify the new limits by running:

launchctl limit maxfiles

The response output should look something like this:

maxfiles    65536          200000

Mac OS X Older Versions

Start by checking the current open file limit values with:

launchctl limit maxfiles

The response should look something like this:

maxfiles    10240          10240

The first column is the soft limit and the last column is the hard limit.

To adjust the maximum open file limits in OS X 10.7 (Lion) up to but not including OS X Yosemite, perform the following steps:

1. Edit (or create) /etc/launchd.conf and increase the limits by adding:

limit maxfiles 65536 200000

2. Save the file and restart the system for the new limits to take effect.

3. After restarting, verify the new limits by running:

launchctl limit maxfiles

The response output should look something like this:

maxfiles    65536          200000