What are different aspects of volume testing?

Volume is a non functional requirement of any software system or application and therefore rightly falls under the category of non functional testing methodologies. Non functional testing methodologies are often misunderstood due to over lapping of scope between the several non functional concepts.

- Volume testing as the name suggests is the testing of a software system or application with a significant amount of data.
- The data can be meaningful or meaning less.
- The significant volume of data which is being used for volume testing cam be of size of a file of interface which has been taken as the subject of the volume testing or it can be of the size of a database either large or small.
- For carrying out the volume testing on any particular software system or application with a specific size of data base, the size of data base is increased to that extent and the testing is carried out on it.

We can take another example in which the software system or application needs to interact with some file of an interface. The file can be of any format whether .txt, .xml, .html, .dat and so on. We can think of this interaction as an action to be performed like reading and writing on to and from the particular file. In this case we will first create a sample file similar to the file size we want and then we will carry out the volume testing on that file and its functionality and specifications.

SOME IMPORTANT POINTS
- Volume testing is also referred to as stability testing when it comes to terms of performance.
- The volume testing is aimed at finding the vulnerabilities of a software system or application in respect to its data handling capability when it comes to handle exceptionally large amounts of data for a prolonged period of time.
- Sometimes it may seem to you that the volume testing is much similar to load testing and stress testing, but the objective of the volume testing actually makes the difference.
- Volume testing differs from load testing and stress testing differs when it comes to the expected result and what is actually being simulated?
- At first it may seem like does significance of volume really matters?
- But when you start analyzing, you will discover that indeed volume has a great deal to do with the non functional requirements of a software system or applications.
- Volume testing becomes important while setting up a web server or a client server or while making changes to it.
- The first question that arises while setting up a network or a system is that whether or not it will be able to handle huge expected volume of data?
- The objective of volume testing is to ensure that the whole software system or application works properly and processes data correctly within the physical and logical boundaries of the system while still maintaining the standard of performance.
- One thing to be noted is that the volume testing focuses on determining the robustness and reliability of the software system rather than determining the responsiveness of the software system.

Volume tests - Volume Testing of Batch Processing Systems

Capacity drivers in batch processing systems are also critical as certain record types may require significant CPU processing, while other record types may invoke substantial database and disk activity. Some batch processes also contain substantial aggregation processing, and the mix of transactions can significantly impact the processing requirements of the aggregation phase.

In addition to the contents of any batch file, the total amount of processing effort may also depend on the size and makeup of the database that the batch process interacts with. Also, some details in the database may be used to validate batch records, so the test database must match test batch files.


Before conducting a meaningful test on a batch system, the following must be known :
- The capacity drivers for the batch records.
- The mix of batch records to be processed, grouped by capacity driver.
- Peak expected batch sizes (check end of month, quarter and year batch sizes).
- Similarity of production database and test database.
- Performance Requirements.


Batch runs can be analyzed and the capacity drivers can be identified, so that large batches can be generated for validation of processing within batch windows. Volume tests are also executed to ensure that the anticipated numbers of transactions are able to be processed and that they satisfy the stated performance requirements.

Volume tests - Volume Testing of Messaging systems

Volume tests are often most appropriate to messaging, batch and conversion processing type situations. In a volume test, there is often no such measure as response time. Instead, there is usually a concept of throughput. A key to effective volume testing is the identification of the relevant capacity drivers. A capacity driver is something that directly impacts on the total processing capacity. For a messaging system, a capacity driver may well be the size of messages being processed.

Most messaging systems do not interrogate the body of the messages they are processing, so varying the content of the test messages may not impact the total message throughput capacity, but significantly changing the size of the messages may have a significant effect. However, the message header may include indicators that have a very significant impact on processing efficiency. For example, a flag saying that the message need not be delivered under certain circumstances is much easier to deal with than a message with a flag saying that it must be held for delivery for as long as necessary to deliver the message, and the message must not be lost. In the former example, the message may be held in memory, but in the later example, the message must be physically written to disk multiple times.

Before conducting a meaningful test on a messaging system, the following must be known:

- the capacity drivers for the messages.
- the peak rate of messages that need to be processed, grouped by capacity driver.
- the duration of peak message activity that needs to be replicated.
- the required message processing rates.


A test can then be designed to measure the throughput of a messaging system as well as the internal messaging system metrics while that throughput rate is being processed. Such measures would typically include CPU utilization and disk activity. It is important that a test be run, at peak load, for a period of time equal to or greater than the expected production duration of peak load.

Purpose of Volume Testing and what are its features.

Volume testing belongs to the group of non-functional tests. Huge amount of data is processed through the application (which is being tested) in order to check the extreme limitations of the system.
- Volume testing refers to testing a software application for a certain data volume.
- Volume testing can (and should) be used in component testing.
- Volume testing will also be undertaken (normally) as part of the User Acceptance test.
- Volume testing is used to find faults and give credible information about the state of the component, on which business decisions can be taken.
- Volume testing might take place to confirm that the central core architecture is the one to proceed with.
- Developers across customers & finish users can do. The tests can be outsourced to a testing laboratory that specializes in performance testing.

Examples:
- Online system: Input fast, but not necessarily fastest possible, from different input channels.
- Database system: The database should be very large. Every object occurs with maximum number of instances.
- File exchange: Especially long files. Maximal lengths. Lengths longer than typical
maximum values in communication protocols.
- Disk space: Try to fill disk space everywhere there are disks.

Volume test is interesting if
• The volume test is not executed before.
• Does the system always has the necessary memory resources?
• Can we guarantee this if several systems share the hardware?
• Is it guaranteed that no larger data volumes than specified will occur?
• Is there a low risk if data volume turn greater than specified anyway but the
system does not work well enough then?