Once, long ago, there was an engineer who broke the operating system particularly badly. Now, if you’ve implemented important software for any serious length of time, you’ve seriously screwed up at least once — but this was notable for a few reasons. First, the change that the engineer committed was egregiously broken: the machine that served as our building’s central NFS server wasn’t even up for 24 hours running the change before the operating system crashed — an outcome so bad that the commit was unceremoniously reverted (which we called a “backout”).
Decommissioning is process to remove one or multiple datanodes from Hadoop.
To decommission a datanode you need to use following process:
Login to namenode host.
Add follwoing configuration in/home/guest/hadoop-2.5.1/etc/hadoop/hdfs-site.xml
After adding dfs.hosts.exclude property you need to restart HDFS.
isl-0.15 is required to build GCC with the Graphite loop optimizations. You can download the isl-0.15 from ftp://gcc.gnu.org/pub/gcc/infrastructure/
# bunzip2 isl-015.tar.bz2
# tar -xvf isl-0.15
# ./configure --prefix=/usr/local/isl-0.15 --with-gmp-prefix=/usr/local/gmp-4.3.2
# make && make install
To perform syntax check and dry run for ansible playbook use following command:
ansible-playbook -i hosts_file --syntax-check --list-tasks playbook.yml
where, –syntax-check is used to check syntax of a playbook & –list-tasks is to all tasks that are executed.
DBMS_OUTPUT package is the standard way to "print"
output from PL/SQL. The way
DBMS_OUTPUT works is like a
buffer. Your Node.js application code turns on
DBMS_OUTPUT buffering, calls some PL/SQL code that puts
text into the buffer, and then later fetches from that buffer. Note:
any PL/SQL code that calls
DBMS_OUTPUT runs to completion
before any output is available to the user. Also, other database
connections cannot access your buffer.