WebSphere MQ Admin Interview Questions And Answers
1. What Is Mq And What Does It Do?
Answer: MQ stands for MESSAGE QUEUEING. WebSphere MQ allows application programs to use message queuing to participate in message-driven processing. Application programs can communicate across different platforms by using the appropriate message queuing software products.
2. What Is Sslpeer In Ibm Websphere Mq?
Answer: if you connected MQ via SSL. SSLPEER is a String usually DN (Distinguished Name) of MQ Client which connect to QueueManager securely using QueueManager. This is a mechanism WMQ uses to identify the client. In case of Java or JMS client, SSLPEER is DN of client certificate stored in its keyStore and sent to the server during SSL handshake.
3. What are the benefits that corporations can have through IBM Websphere MQ?
Answer: Organizations and corporations can simply send bulk messages over complex networks. There are no strict protocols that need to be followed. Even if they are, the same can be managed very easily. Enterprises can make sure of quick information delivery to the destinations and can always have the things done in the best possible manner.
4. What do you mean by Asynchrony in IBM Websphere MQ?
Answer: In the queue process, the process of sending or exchange of any message doesn’t depend on the time. This is exactly what that makes both the sender, as well as the receiver to be decoupled if the need of same is there. There is actually no need for the sender to wait for getting the acknowledgment regarding the delivery of the message from the receiver. IT can continue with this next task. This process is basically considered as Asynchrony in IBM Websphere MQ.
5. What is the difference between the dead letter queue and backout queue in Websphere MQ?
Answer: This is a follow question of previous MQ interview question “What is dead letter queue in MQ Series”. As we have seen that dead letter queue is used to store messages which are received for the nonexistent queue. On the other hand, the backout queue is an application-specific queue. If MQ client is not able to process message and ask for redelivery, the message is redelivered to the client with the incremented delivery count. Once this delivery count crossed a configured threshold message is moved to back-out queue for later processing or error handling. In short if MQ Series are not able to deliver a message to the client after a preconfigured attempt, WMQ moves message to backout queue.
6. What are the Different Types Of Queues?
Queues can be characterized by the way they are created:
1. Predefined queues are created by an administrator using the appropriate MQSC or PCF commands. Predefined queues are permanent; they exist independently of the applications that use them and survive Web Sphere MQ restarts.
2 Dynamic queues are created when an application issues an MQOPEN request specifying the name of a model queue. The queue created is based on a template queue definition, which is called a model queue.
7. How to determine if full repositories are in Synch?
Answer: SYSTEM.CLUSTER.REPOSITORY.QUEUES should have the same depth. Also, you should find something in your error logs if it fails. If the channels between the two FRs are able to run, trust IBM, and assume all good use runmqsc to display all cluster objects. Redirect the output into a file Analyze both files for differences.
8. Is the procedure of installation the IBM WebSphere MQ on Aix similar to that for Windows?
Answer: Yes, all the requirements are the same except for a few basic ones. For older versions of Windows such as 2000 and XP, it needs some customized settings in the application. It is actually free from the network protocols and thus users have no reasons to worry about this.
9. What is the concept of switching?
Answer: Ina network, there can be a very large number of nodes. Practically it is not possible to establish a direct physical connection between them all. Of course, this can enhance the cost up to a great extent and can make the network very complex. Thus, the concept of switching is considered. It basically acts as a temporary path that is established between a sender and a receiver for message transfer. The connection is terminated after the message is sent. Because not all the nodes need channels all the time, this concept can be applied. It is having a lot of advantages. All the data that seems to be sent on priority can be assigned sent immediately by stopping other operations.
10. What is Asynchrony?
Answer: With message queuing, the exchange of messages between the sending and receiving programs are independent of time. This means that the sending and receiving application programs are decoupled; the sender can continue processing without having to wait for the receiver to acknowledge receipt of the message. The target application does not even have to be running when the message is sent. It can retrieve the message after it is has been started.
11. Difference Between Mqsc Commands And Control Commands?
MQSC Commands: These commands are used to handle the admin related functions for the components that are present in the MQ Series. In general MQSC commands are used for creating and maintaining Message channels, Queue Managers, Clusters etc…
Control Commands: These commands are used to manage the processes and services that are helpful in the functioning of the MQ Series. In general, these commands are used for Channel listener, Channel Initiator, Trigger monitor etc…
12. What is the Metrics application?
Answer: The new IBM Connections Metrics application provides a comprehensive set of quantitative and qualitative metrics that help measure the business value of IBM Connections to your organization. IBM Connections uses IBM Cognos Business Intelligence to generate reports that users can view directly in IBM Connections. Metrics reports can provide your organization with the information and insight to make the right, fact-based business decisions.
For example, you can generate the following Metrics reports at the global level:
Number of unique authenticated (and anonymous) visitors for the entire system and for individual components Number of users who created or updated content Most popular content, based on number of visits, follows, or recommendations At the community level, you can generate Metrics reports such as the following: Number of unique authenticated (and anonymous) visitors for the community, including its widgets Number of contributors for each widget in a community Most active contributors. Most popular content, based on a number of visits, follows, or recommendations for more information about Metrics, refer to: What are Metrics.
13. What are the differences between the Metrics reporting functionality for IBM Connections 3.0 and IBM Connections 4.0?
Answer: IBM Connections 3.0.1Metrics provides separate reports for each application. Metrics in IBM Connections 4.0 provides one central user interface to display global metrics reports and community metrics reports.
Metrics reports in IBM Connections 3.0.1 are presented using simple Metrics reports in IBM Connections 4.0 are presented in various formats including tables, charts, and other kinds of graphs.
Metrics in IBM Connections 4.0 employs the powerful capabilities of IBM Cognos Business Intelligence to provide customers with more features, including reports, dimensions, customization, and drill up/down.
14. What is the difference between the dead letter queue and backout queue in Websphere MQ?
Answer: As we have seen that dead letter queue is used to store messages which are received for the nonexistent queue. On the other hand, the backout queue is an application-specific queue. If MQ client is not able to process message and ask for redelivery, the message is redelivered to the client with the incremented delivery count. Once this deliveryCountcrossed a configured threshold message is moved to back-out queue for later processing or error handling. In short if MQ Series are not able to deliver a message to the client after a preconfigured attempt, WMQ moves message to backout queue.
15. What exactly do you understand with the term MQ and what it is responsible for?
Answer: MQ abbreviates Message Queuing. When it comes to message-driven processes, IBM enables users to simply keep up the pace with the WebSphere with which all application programs can simply be managed. There is no strict upper limit on the platforms when it comes to communicating and the good thing is a vast support is available from IBM to enable the users to manage everything simply.
16. What is the difference between the local queue and the remote queue in WMQ?
Answer: Rather simple and fact-based MQ Series interview question. This is asked to see whether the candidate is familiar with MQ Series terminology or not. In WebSphere MQ, local queues are a queue on the same queue manager while remote queue refers to queue on different QueueManager.
17. What are the advantages of the MQ?
3. Assured Delivery
18. what is a Message and what does it contain?
Answer: A message is a string of bytes that is meaningful to the applications that use it. Messages are used to transfer information from one application program to another (or between different parts of the same application). The applications can be running on the same platform, or on different platforms.
WebSphere MQ messages have two parts:
1. The application data. The content and structure of the application data are defined by the application programs that use it.
2. A message descriptor. The message descriptor identifies the message and contains additional control information, such as the type of message and the priority assigned to the message by the sending application. WebSphere MQ defines the format of the message descriptor.
19. Mention the Different Types of MQ Queues?
There are four types of Queues Available in Web sphere MQ
Local queue object: A local queue object identifies a local queue belonging to the queue manager to which the application is connected. All queues are local queues in the sense that each queue belongs to a queue manager and, for that queue manager; the queue is a local queue.
Remote queue object: A remote queue object identifies a queue belonging to another queue manager. This queue must be defined as a local queue to that queue manager. The information you specify when you define a remote queue object allows the local queue manager to find the remote queue manager so that any messages destined for the remote queue go to the correct queue manager.
Alias queue object An alias queue allows applications to access a queue by referring to it indirectly in MQI calls. When an alias queue name is used in an MQI call, the name is resolved to the name of either a local or a remote queue at run time. This allows you to change the queues that applications use without changing the application in any way; you merely change the alias queue definition to reflect the name of the new queue to which the alias resolves. An alias queue is not a queue, but an object that you can use to access another queue.
Model queue object A model queue defines a set of queue attributes that are used as a template for creating a dynamic queue.
20. What is Process Definition and what are the attributes does it contain?
Answer: A process definition object defines an application that starts in response to a trigger event on a WebSphere MQ queue manager. The process definition attributes include the application ID, the application type, and data specific to the application.
21. What is Intercommunication?
Answer: In Web Sphere MQ, intercommunication means sending messages from one Queue manager to another. The receiving queue manager could be on the same machine or another; nearby or on the other side of the world. It could be running on the same platform as the local queue manager or could be on any of the platforms supported by Web Sphere MQ. This is called a distributed environment. Web Sphere MQ handles communication in a distributed environment such as this using Distributed Queue Management (DQM).
The local queue manager is sometimes called the source queue manager and the remote queue manager is sometimes called the target queue manager or the partner queue manager.
22. What do you mean by message descriptor?
Answer: A massage doesn’t just contain information that needs to be transferred but it contains other information too. For example, type of message and what exactly its priority is. The same is described in the message descriptor which is defined by WebSphere MQ. It contains all other relevant information about the message and among all of the same, its priority that largely matters.
23. What Is The Difference Between Persistent And Non-Persistent Messages?
Answer: In the Web Sphere MQ, messages can be either persistent or nonpersistent.
Persistent messages are logged and can be recovered in the event of a WebSphere MQ failure. Thus, persistent messages are guaranteed to be delivered once and only once.
Nonpersistent messages are not logged. Web Sphere still guarantees to deliver them not more than once, but it does not promise to deliver them once.
24. What are the advantages of creating Aliases?
Answer: When sending messages Remapping the queue-manager name, Altering or specifying the transmission queue and Determining the destination.
When receiving messages, Using a queue manager as a gateway into the cluster. Gives the different application to different levels of access authority to the target Queue Allows different applications to work with the same queue in a different way Simplifies maintenance, migration and workload balance.
25. What Is Message Driven Process?
Answer: When messages arrive on a queue, they can automatically start an application using triggering. If necessary, the applications can be stopped when the message (or messages) have been processed.
26. What is Transmission Queue?
Answer: Transmission queues are queues that temporarily store messages that are destined for a remote queue manager. You must define at least one transmission queue for each remote queue manager to which the local queue manager is to send messages directly.
27. What are the channel and mention different types of channels in MQ?
Answer: Channels are objects that provide a communication path from one queue manager to another. Channels are used in distributed queuing to move messages from one queue manager to another. They shield applications from the underlying communications protocols. The queue managers might exist on the same, or different, platforms.
Different types of Channels:
1. Sender-Receiver Channels
2. Requester-Server Channels
3. Client Connection channels
4. Server Connection Channels.
5. Cluster Sender.
6. Cluster Receiver Channels
28. What do MQSC Commands are used for?
Answer: You can use MQSC commands to manage queue manager objects, including the queue manager itself, clusters, channels, queues, name lists, process definitions, and authentication information objects.
29. Are the MQSC attributes are Case sensitive?
Answer: MQSC commands, including their attributes, can be written in uppercase or lowercase. Object names in MQSC commands are folded to uppercase (that is, QUEUE and queue are not differentiated) unless the names are enclosed within single quotation marks. If quotation marks are not used, the object is processed with a name in uppercase.
30. What is the Different Logging Methods available?
There are two different types available:
1. Circular: The circular logging is used for restart recovery. It is the default logging method. Circular is used in Development and Testing Queues. Circular logging keeps all restart Data in a ring of log files. Logging fills the first file in the ring, then moves on to the and so on, until all the files are full. It then goes back to the first file in the ring and starts This continues as long as the product is in use, and has the advantage that you never run out of log files.
2. Linear: Linear logging gives you both restart recovery and media recovery. It is used in Production. Linear logging keeps the log data in a continuous Sequence of files. (COMPANY) Space is not reused, so you can always retrieve any record logged from the time that the queue manager was created. As disk space is finite, you might have to think about some form of archiving. It is an administrative task to manage your disk space for the log, reusing Or extending the existing space as necessary.
31. What is Channel initiators and Listeners?
Answer: A channel initiator acts as a trigger monitor for sender channels, because a transmission queue may be defined as a triggered queue. When a message arrives on a transmission queue that satisfies the triggering criteria for that queue, a message is sent to the initiation queue, triggering the channel initiator to start the
appropriate sender channel. You can also start-server channels in this way if you specified the connection name of the partner in the channel definition. This means that channels can be started automatically, based upon messages arriving on the appropriate transmission queue.
You need a channel listener program to start receiving (responder) MCAs. Responder MCAs are started in response to a startup request from the caller MCA; the channel listener detects incoming network requests and starts the associated channel.
32. What is triggering and what are the components?
Answer: WebSphere MQ can start an application automatically when certain conditions on a queue are met. For example, you might want to start an application when the maximum number of messages on a queue reaches a specified number.
This facility is called triggering
There are two ways of triggering:
a. Application triggering
b. Channel Triggering
a) In the case of application triggering the components is Application queue: This is the message queue associated with an application Process: A process definition defines the application to be used to process messages from the application queue. Initiation queue: The queue manager monitors the application queue. If the trigger type of the application queue is set to Every then whenever a message is put to the application queue, the q manager looks into the process definition and puts a message having the application name and other details to the initiation queue Trigger monitor: The trigger monitor gets the trigger message from the initiation queue and starts the program specified.
b) For channel triggering the transmission, queue is monitored and when messages are put in the transmission queue, the q manager puts a message in the channel initiation queue. The channel initiator is the program which monitors the initiation queue and starts the sender MCA. For the message to reach the target queue, the channel listener has to be running in the target queue manager
33. In IBM WebSphere MQ, how you will define a message?
Answer: A message is basically considered as a string of bytes which contains something useful for the machine or for the user. Generally, messages are deployed when it comes to the sharing of information among different nodes. It doesn’t matter whether the application runs on platforms which are different from each other.
34. What Is Ccdt File On Websphere Mq Or Wmq?
Answer: CCDT file or Client Channel Definition table is a binary file which contains connection details required by MQ clients e.g. Java application using JMS to connect to MQ Server. In order to connect to MQ Server, MQ clients need MQ Server hostname, MQ Server port name, and server channel name. All these details are encapsulated in CCDT file named as AMQCLCHL.TAB. In order to create MQ Connection, MQ clients need the location of this file, which is provided as configuration. most of MQ errors comes either with incorrect CCDT files.
35. What Is The Effect Of Using Persistent Messages?
Answer: Persistent messages are usually logged. Logging messages reduces the performance of your application, so use persistent messages for essential data only. If the data in a message can be discarded if the queue manager stops or fails, use a nonpersistent message
36. What Is Mq Server?
Answer: A Web Sphere MQ server is a queue manager that provides queuing services to one or more clients. All the Web Sphere MQ objects, for example, queues, exist only on the queue manager machine (the Web Sphere MQ server machine), and not on the client. A Web Sphere MQ server can also support local Web Sphere MQ Applications.
37. What is the difference between the control commands and the MQS commands?
Answer: Control commands are used when it comes to managing the services, as well as different processes related to messaging. Most of the time, these commands are deployed for the channel listener, triggering or for the integration of the same. On the other side, the MQS commands are useful when it comes to functions which are related to the tasks performed by an administrator. It is also possible to create Queue Managers and channels through these commands
38. What is Message Channel agent (MCA)?
Answer: A message channel agent (MCA) is a program that controls the sending and receiving of messages. There is one message channel agent at each end of a channel. One MCA takes messages from the transmission queue and puts them on the communication link. The other MCA receives messages and delivers them onto a queue on the remote queue manager.
A message channel agent is called a caller MCA if it initiated the communication; otherwise, it is called a responder MCA.
39. How can U make the existing Queue Manager as a default Queue Manager?
Answer: On Windows systems, use the Web Sphere MQ Services snap-in to display the properties of the queue manager, and check the Make queue manager the default box. You need to stop and restart the queue manager for the change to take effect.
40. What is the dead letter queue in IBM MQ Series?
Answer: Dead letter Queue in WebSphere MQ is a queue which is used by QueueManager to archive messages for a nonexistent queue.
For an example of QueueManagerQMGR, receives a message for queue ABC and if it didn’t exist on that QueueMangaer then the message will be routed to dead letter queue.
41. What is commit and Back Out units of work?
Answer: When a program puts a message on a queue within a unit of work, that message is made visible to other programs only when the program commits the unit of work.
Commit: To commit a unit of work, all updates must be successful to preserve data integrity. If the program detects an error and decides that the put operation should not be made permanent, it can back out the unit of work.
Back Out: When a program performs a back out, WebSphere MQ restores the queue by removing the messages that were put on the queue by that unit of work. The way in which the program performs the commit and back out operations depends on the environment in which the program is running.
42. What is the difference between community metrics and global metrics?
Answer: IBM Connections provides metrics on two levels: global and community. Global metrics report on overall usage; for example, the total number of people who logged into IBM Connections last week. Community metrics report on a particular community; for example, the number of people who logged into the Sales community last week.
43. How does Metrics track events?
Answer: The Metrics application uses the Event Tracker to track events in IBM Connections applications. The event tracker records user actions in Connections. For example, an event is recorded every time a Connections user reads a blog entry, creates a “To do” item in an activity, updates a wiki page, or follows a community. These events are then used to calculate various metrics based on their timing and frequency.