This post provides the various queries that can be used to monitor Undo space usage. The Undo Space once allocated won’t be deallocated to the OS, by default. But the space can be reused by other transactions once the UNDO_RETENION (or TUNED_UNDORETENTION period) is met. 1. To check the current size of the Undo tablespace: […]
Archives for August 2018
Script To Get Tablespace Utilization In Oracle Database 12c
This is a script to get the tablespace utilization in Oracle Database 12c. You can use this script to get the tablespace utilization ALLOCATED(MB), USED(MB) and Used parentage for all containers tablespaces. sqlplus -s / as sysdba set pages 80 set lin 120 set echo off set feed off column PCT format 999.99 column tbspce […]
How to Audit File Access on Linux
On Linux there is an audit RPM named audit, which provides auditd service to monitor the processes and the commands as well. Using audit RPM we can audit some simple file operation like read, write and execution. This post will introduce a method to monitor the file access on the Linux system. Like “When the […]
How to disable the default apache “Welcome Page” in CentOS/RHEL 7
The Problem When you install Apache 2, you would see the “Welcome Page” as shown below when you first open the URL IP of the server. You may not find this page in the default Document Root “/var/www/html” as well. How can we disable this page and have our own page being displayed? The Solution […]
CCA 131 – Rebalance the cluster
Note: This post is part of the CCA Administrator Exam (CCA131) objectives series In a long-running cluster, there might be an unequal distribution of data across Datanodes. This could be due to failures of nodes or the addition of nodes to the cluster. To make sure that the data is equally distributed across Datanodes, it […]
CCA 131 – Commission/decommission a node
Note: This post is part of the CCA Administrator Exam (CCA131) objectives series Cloudera Manager makes it very simple to add and remove hosts in a cluster. All host management operations in Cloudera Manager are done from the Hosts screen. In this post, we will go through the steps of Commissioning and decommissioning a host […]
CCA 131 – Add a service using Cloudera Manager
Note: This post is part of the CCA Administrator Exam (CCA131) objectives series To start with we have just installed few services like HDFS, YARN, and zookeeper in our CDH setup. The Cloudera Manager enables you to add any other service later on. As a part of the exam, you may be asked to add […]
CCA 131 – Add a new node to an existing cluster
Note: This post is part of the CCA Administrator Exam (CCA131) objectives series Cloudera Manager makes it very simple to add and remove hosts in a cluster. All host management operations in Cloudera Manager are done from the Hosts screen. In this section, we will go through the steps of adding a new host to […]
CCA 131 – Install CDH using Cloudera Manager
Note: This post is part of the CCA Administrator Exam (CCA131) objectives series In the last post, we have seen how to install the Cloudera server manager and Cloudera Manager agents. In this post, we will begin installing the CDH cluster using the Cloudera Manager. You can point your browser to http://[cloudera manager host]:7180 and […]
CCA 131 – Install Cloudera Manager server and agents
Note: This post is part of the CCA Administrator Exam (CCA131) objectives series Cloudera Installation Paths There are 3 paths in which the cloudera cluster can be installed and configured. PATH A – Automated Installation PATH B – Using Cloudera Manager with local Parcel/Packages PATH C – Manual Installation using tarballs Cloudera installation Phases Whichever […]