Problem to mount NFS : mount: wrong fs type, bad option, bad superblock

Sometime, we may get error as  mount: wrong fs type, bad option, bad superblock while trying to mount NFS file in ubuntu. For my case, i faced the problem showing the error as:

The reason behind it that for several filesystems (e.g. nfs, cifs) we might need a /sbin/mount. helper program.
As we are trying to mount NFS. The /sbin/mount.nfs helper program is provided by nfs-common. We can install it with:

sudo apt-get update
sudo apt install nfs-common

On the other hand, if we are trying to mount CIFS, the helper program is provided by cifs-utils. We can install it using below command:

sudo apt install cifs-utils


Then we can mount our target as:
We will have to create a directory where to mount the nfs,

sudo mount :/ /

Get elapsed time for an individual command

In sqlplus, to see the elapsed time for an individual query, we can use the "set timing on" command.

SQL> set timing on;

SQL> select surname from personal_details where firstname='udvas';

Elapsed: 00:00:02.52

Again, the "set timing on" command is a SQL*Plus command, but we can measure run time for Oracle SQL with a variety of Oracle tools.

Sometimes when working on SQL command optimizations, all that is desired is a rough timing estimate; namely, the SQL*Plus client elapsed execution time, or simple clock time. Often that simple metric is sufficient for some very basic tuning needs. SQL*Plus has a built-in capability to do exactly this - it is the SET TIMING  command. It essentially records the clock time before and after the SQL command execution, then displays the run time difference.

This commands works for the single command.

VisualVM for monitoring remote jvm

Using VisualVM we can monitor all the running Java Process and status of JDK behind these processes. VisualVM can be found inside the JDK bin directory.

By running VisualVM, by default we can access the locally run processes. To get the Remote Server processes, we have to connect with that server through credential. And in the target server, jstatd must be in running.

jstatd: 

Monitors Java Virtual Machines (JVMs) and enables remote monitoring tools to attach to JVMs. This command is experimental and unsupported. 

The jstatd command is an RMI server application that monitors for the creation and termination of instrumented Java HotSpot VMs and provides an interface to enable remote monitoring tools to attach to JVMs that are running on the local host.

To run jstatd, java security permission is required. For this purpose, at the starting of jstatd, argument will have to be passed in the command line as:

 jstatd -J-Djava.security.policy=/home/paul/jstatd.all.policy

content of jstatd.all.policy  is as:

bash-4.3$ cat /home/oracle/jstatd.all.policy

grant codebase "file:${java.home}/../lib/tools.jar" {

   permission java.security.AllPermission;

};

It permits only the min required security related permission .

SVN Quick Note : Check all revision and download specific revision

We can use the below command for the revision history with commit message

svn log -l5 -v

To dowload specific revision version from SVN:
svn checkout http://10.78.11.131/svn/mbsdb@7 testsvn/

* Here 7 is the revision no.
** testsvn is the target directory where to download