Configuring Redis for use by HCL Detect

HCL Detect uses Redis, an in-memory data structure store.

You might be required to address certain OS-level requirements to ensure that Redis runs efficiently. As the Installation Process is carried out, you might face warnings similar to the following:

Warning:

The operating system in this host is not optimally configured to run Redis, details:

overcommit_memory is set to 0. Redis background save process may fail under low memory conditions. To fix this issue add ‘vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect. For more details, please refer to http://redis.io/topics/admin
when Transparent Huge Pages (THP) support is enabled in the Linux kernel (as is the case now), it can lead to high latency when Redis forks to persist data to disk. THP support can be disabled by executing the command ‘echo never > /sys/kernel/mm/transparent_hugepage/enabled' as root, and adding it to your /etc/rc.local in order to retain the setting after a reboot. When making it permanent, make sure that the rc.local file has the execution permission for the owner (if this file is a symlink, ensure that the permission is set for actual file being linked). For more details, please refer to http://redis.io/topics/admin
unable to enforce the TCP backlog settings of 511 yet-to-be-listened TCP connections in Redis. To fix this issue add ‘net.core.somaxconn=511' to /etc/sysctl.conf and then reboot or run the command ‘sysctl -w net.core.somaxconn=511' for this setting to take effect immediately, but only until the next reboot. For more details, please refer to http://redis.io/topics/admin

Ensure that, if/when these errors are displayed, the changes suggested by the error messages are put in place.