How do I modify "/sys/kernel/mm/transparent_hugepage/enabled"
sudo apt install sysfsutils
and append a line with that setting to
kernel/mm/transparent_hugepage/enabled = never
This is the cleanest solution, because it keeps all the sysfs configuration in one place instead of relying on custom start-up scripts. The other answers, with the scripts and conditional expressions, are suitable if you don't know through which path the kernel will expose that setting, i. e. if you don't even have a rough idea of the kernel version running on the affected machine.
The MongoDB docs have a few suggestions. http://docs.mongodb.org/manual/reference/transparent-huge-pages/
The "preferred" way is to edit
/etc/default/grub and append
GRUB_CMDLINE_LINUX_DEFAULT then run
update-grub to rebuild the GRUB configuration.
The following two-liner will do just that. Make sure to verify the output!
sed -r 's/GRUB_CMDLINE_LINUX_DEFAULT="[a-zA-Z0-9_= ]*/& transparent_hugepage=never/' /etc/default/grub | sudo tee /etc/default/grub sudo update-grub
update-grub is a wrapper for
grub-mkconfig will clobber entries in
/etc/default/grub with those from
If by chance you are running on AWS, you will need to instead edit
The "alternate" method is to edit
/etc/rc.local and add the following before
if test -f /sys/kernel/mm/transparent_hugepage/khugepaged/defrag; then echo 0 > /sys/kernel/mm/transparent_hugepage/khugepaged/defrag fi if test -f /sys/kernel/mm/transparent_hugepage/defrag; then echo never > /sys/kernel/mm/transparent_hugepage/defrag fi if test -f /sys/kernel/mm/transparent_hugepage/enabled; then echo never > /sys/kernel/mm/transparent_hugepage/enabled fi
Personally, I ended up doing both the "preferred" and "alternate" methods since they aren't mutually exclusive and it eliminates the warning about defrag.
* Worked for me on Ubuntu 14.04, MongoDB 3.0.2, and AWS.
Here's a solution that has been tested to work on Ubuntu 16.04 on AWS EC2. Ubuntu 16.04 uses the systemd init system, and this config file expresses that these settings should be changed before MongoDB boots up.
Create a file named
/etc/systemd/system/mongodb-hugepage-fix.service and add the following content:
[Unit] Description="Disable Transparent Hugepage before MongoDB boots" #WARN: check service name on your system # If you are using MongoDB Cloud, service name is "mongodb-mms-automation-agent.service" Before=mongodb.service [Service] Type=oneshot ExecStart=/bin/bash -c 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' ExecStart=/bin/bash -c 'echo never > /sys/kernel/mm/transparent_hugepage/defrag' [Install] #WARN: check service name on your system # If you are using MongoDB Cloud, service name is "mongodb-mms-automation-agent.service" RequiredBy=mongodb.service
To load the file into systemd:
To activate the file as a boot-time dependency of MongoDB
systemctl enable mongodb-hugepage-fix
If you want to activate the changes immediately (before the next boot)
systemctl start mongodb-hugepage-fix systemctl restart mongod
This solution is not suitable for Ubuntu 14.04, which uses the Upstart init solution instead of systemd.