So we all know that when troubleshooting MySQL crashes or any other processes in that regard, we simply enable core files to be dumped when the appropriate signal it triggered. To get the best results, we’d set the core file size limit everywhere to unlimited and be done with it, but what if you want to limit that to a certain size? I stumble to a small confusion lately when doing this for MySQL, so let me share quickly.
First, for MySQL, mysqld_safe would use ulimit to set the core-file-size value you pass to it. Now remember according to the manual, this value should be in blocks (some documentation says its in chunks of 1024 bytes). However, according to my experience on CentOS 6, this is the physical block size of the device where your core_pattern is pointed to.
[root@centos6 ~]# ulimit -a ... core file size (blocks, -c) 0 [root@centos6 ~]# cat /proc/sys/kernel/core_pattern /var/tmp/core [root@centos6 ~]# blockdev …[Read more]