Monthly Archives: March 2019


mysql 8.0 – Show detailed warning messages executing mysqlimport or mysql LOAD DATA

1) Add log-warnings and max error count statements to /etc/my.cnf These configuration options cause detailed warning messages to be written in /var/log/mysql.log [mysqld] log-warnings max-error-count=9999999999 2) Start the mysql client session using the –show-warnings option mysql -u… -p -hlocalhost –show-warnings Adding the –show-warnings option […]


mysql /etc/my.cnf

innodb_buffer_pool_size = 12G # 60% – 70% of your RAM size innodb_log_buffer_size = 16M # 16M or 32M innodb_log_file_size = 3G # 25% of buffer pool size innodb_write_io_threads = 32 # 32 based on core and drive count, 64 is […]


GFS2: Global File System 2 on RHEL CentOS

Global File System 2 or GFS2 is a shared-disk file system for Linux computer clusters. GFS2 differs from distributed file systems (such as AFS, Coda, InterMezzo, or GlusterFS) because GFS2 allows all nodes to have direct concurrent access to the same shared block storage. In addition, GFS or GFS2 can also be used as […]


Installing ZFS on RHEL 7 CentOS 7

Instructions By default, ZFS is not available in the standard CentOS repository. We will need to include some 3rd party repositories here. sudo rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm sudo rpm -Uvh http://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm sudo rpm -Uvh https://forensics.cert.org/cert-forensics-tools-release-el7.rpm sudo rpm -Uvh http://download.zfsonlinux.org/epel/zfs-release.el7_6.noarch.rpm sudo yum […]


ZFS Performance: Mirror vs RAIDZ vs RAIDZ2 vs RAIDZ3 vs Striped

Performance difference among different ZFS types, such as mirror, RAIDZ, RAIDZ2, RAIDZ3, Striped, two RAIDZ vdevs vs one RAIDZ2 vdev etc… Background CPU: Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz / quard cores / 8 threads OS: CentOS Linux release 7.3.1611 […]


How to fix ZFS after updating to a newer kernel

Step 1: Clean up and Reinstall DKMS Modules Most of the time, the ZFS on Linux messes up the DKMS modules after the update. I suggest to clean up and reinstall DKMS modules once again. As of December 12, 2018, […]


Improving ZFS performance

A Good 64-bit CPU + Lots of Memory Traditionally, we are told to use a less powerful computer for a file/data server. That’s not true for ZFS. ZFS is more than a file system. It uses a lot of resources […]


mysql 8.0 task list

# mysql [-h hostname] -u root -p Create a database mysql> create database [databasename]; List all databases . mysql> show databases; Switch to a database mysql> use [db name]; List tables in the db. mysql> show tables; To see database’s […]