Error - mongod shell doesn't start, /data/db doesn't exsist

Error - mongod shell doesn't start, /data/db doesn't exsist


If you face this error while starting MongoDB (mongod), most probably there are 2 reasons for this -

a.  /data/db is not exist at all
b. mongod process don't have access on /data/db

Solution :-

The default db path for mongodb is /data/db/.
So when you run:

Conductor Node in Datastage

Below is the sample APT CONFIG FILE ,see in bold to mention conductor node.


{
node "node0"
{
fastname "server1"
pools "conductor"
resource disk "/datastage/Ascential/DataStage/Datasets/node0" {pools "conductor"}
resource scratchdisk "/datastage/Ascential/DataStage/Scratch/node0" {pools ""}
}

What can you delete to free up disk space in IBM InfoSphere Information Server

What can you delete to free up disk space in IBM InfoSphere Information Server when disks are becoming full?

What to do ????

Here are some things you can do to clean up space:

• Clear the &PH& file in the Project directory. There is a &PH& directory in each DataStage project directory, which contains information about active stages that is used for diagnostic purposes. The &PH& directory is added to every time a job is run, and needs periodic cleaning out.
  

DataStage Configuration file : Explained - 3

Below is the sample diagram for 1 node and 4 node resource allocation:

 

DataStage Configuration file : Explained - 2

1.    When configuring an MPP, you specify the physical nodes in your system on which the parallel engine will run your parallel jobs. This is called Conductor Node. For other nodes, you do not need to specify the physical node.  Also, You need to copy the (.apt) configuration file only to the nodes from which you start parallel engine applications. It is possible that conductor node is not connected with the high-speed network switches. However, the other nodes are connected to each other using a very high-speed network switches. How do you configure your system so that you will be able to achieve optimized parallelism ??

1.    Make sure that none of the stages are specified to be run on the conductor node.

2.    Use conductor node just to start the execution of parallel job.

3.    Make sure that conductor node is not the part of the default pool.

DataStage Configuration file : Explained - 1

The Datastage configuration file is a master control file (a textfile which sits on the server side) for jobs which describes the parallel system resources and architecture. The configuration file provides hardware configuration for supporting such architectures as SMP (Single machine with multiple CPU , shared memory and disk), Grid , Cluster or MPP (multiple CPU, mulitple nodes and dedicated memory per node). DataStage understands the architecture of the system through this file.

This is one of the biggest strengths of Datastage. For cases in which you have changed your processing configurations, or changed servers or platform, you will never have to worry about it affecting your jobs since  all the jobs depend on this configuration file for execution. Datastage jobs determine which node to run the process on, where to store the temporary data, where to store the dataset data, based on the entries provide in the configuration file. There is a default configuration file available whenever the server is installed.

Using Configuration Files in Data Stage Best Practices & Performance Tuning

The configuration file tells DataStage Enterprise Edition how to exploit underlying system resources (processing, temporary storage, and dataset storage). In more advanced environments, the configuration file can also define other resources such as databases and buffer storage. At runtime, EE first reads the configuration file to determine what system resources are allocated to it, and then distributes the job flow across these resources.

When you modify the system, by adding or removing nodes or disks, you must modify the DataStage EE configuration file accordingly. Since EE reads the configuration file every time it runs a job, it automatically scales the application to fit the system without having to alter the job design.

Difference between scratch disk and resource scratch disk

The Only difference is :

• Scratch Disk is for Temporary storage (Like RAM in our PC)