MapR 5.0 Documentation : cores dir

In the event of a core dump on a node, MapR writes the core file to the /opt/cores directory by default. However, you can specify a different location for storing core files by using the standard Linux core_pattern file:

/proc/sys/kernel/core_pattern

The hoststats service monitors the active core directory and raises an alarm when a core file is written to that location.

A valid location in the core_pattern file is a full path to the directory you want to use. For example: 

/tmp/dir1/cores/%e.core.%p.%h

The default core directory (/opt/cores) will still be used if core_pattern does not contain a full path or if it uses the "|" redirection feature. The default directory is also used if the core_pattern file contains the default value of core. For details about the standard Linux % specifiers that you can use to name core files, see the core man page.

If disk space on a node is nearly full, MapR automatically reclaims space by deleting core files. To prevent a specific core file from being deleted, rename the file to start with a period (.). For example:

mv mfs.core.2127.node12 .mfs.core.2127.node12