Identify and document the current system components and ...web1.muirfield-h.schools.nsw.edu.au/technology/resource… · Web viewIn general, the word audit is associated with some

Configure and test applications for multi-user network use

Identify and document current system components and configuration 2

The audit 2Identifying existing hardware and software 3

Identify and map system interaction 7What data is required 7Multi-user data access considerations 8

Examine all existing applications and plan required upgrades or reconfigurations 11

Network performance 11Other system requirements 12System incompatibilities 14Identifying additional resources and installation procedures17

Test reconfiguration for successful interface with existing system 18

Planning the test 19Conducting the test 20Running the test 21Putting into production 22

Summary 23Check your progress 23

Reading: Configure and test applications for multi-user network use 12005

Identify and document current system components and configuration

The auditBefore you can determine the impact of a new application on your network you must have a clear understanding of the current network’s components. One way of gaining this understanding is to identify and document the network through audits of hardware and software.

The word audit is used in many contexts, particularly with respect to financial accounts. In general, the word audit is associated with some form of official investigation to ensure quality.

Reflection

Why do you think management might request a network systems audit?

Feedback

A network systems audit will give you a list of all the components and resources in the network, their configurations, and relationships. Having accurate documentation of your network is useful in many ways. It can help you with planning, preventative maintenance, disaster recovery, impact assessments, OH&S, and even compliance.

Audit documentation

The deliverable or outcome of a network systems audit is usually a report or a database listing all components. The policy document at your organisation may require that a hardware and software register be established after a network systems audit is performed. Once the register is established, there is a need to follow an ongoing process of updating and re-evaluating the register to keep it current and synchronised with changes to the actual systems.

2 Reading: Configure and test applications for multi-user network use2005

Reflection

If you were to do a network audit, what sorts of things would you include in your investigation?

Feedback

You might like to include the details of servers, desktop computers, peripheral devices such as printers and backup devices, network devices such as routers, operating systems, applications, etc.

Identifying existing hardware and softwareIn this topic we are concerned with performing a network audit as a preliminary to installing new multi-user applications.

Reflection

What do you think such an audit is concerned with?

Feedback

This type of audit is an investigation into the network systems which will support or be affected by the installation of a software package. It is useful to undertake this investigation prior to an upgrade or purchase of new software.

Activity

Think about your current computer for a moment. Write down a list of characteristics of your computer that might affect the correct running of a software application.


Feedback

When installing new software, some of the features that will effect the correct operation of a software package include the physical configuration of your machine. You need to consider the hardware components that make up your computer. An audit might collect data on details such as:

Type of machine (PC, Apple, etc.)

CPU type and speed

Memory

Hard disk size

Installed cards (network cards, sound cards, graphics cards)

Peripheral devices such as a CD ROM drive, a printer, etc.

The other important issue to consider is the list of software applications that are already installed on the computer.

What is the operating system?

What applications are installed?

What is the version of the application?

s the software properly licensed?

In addition, it is often useful to audit the applications which are most commonly used by the staff, how and when they use the applications and which applications are most critical to their job roles. This can help with optimising the computer systems to be more efficient and effective, depending on who uses which systems the most. It can also help you to identify critical applications that need to be included in an investigation of software interoperability. Software interoperability will be discussed in more detail, later in the topic.

Analysing existing networks

There is a wide range of administration tools supplied with the operating system or available from third party vendors. These tools and utilities can provide very sophisticated diagnostics of network hardware and software.

Often you should be using these tools purely to confirm information that is already in the network register, and determine the current capacity of the systems.


Reflection

Why is it necessary to confirm the software and hardware registries in this case? What would happen if we chose a new software application based on incorrect network documentation?

Feedback

It is possible that we might select software which is not suitable for our network and it behaves unexpectedly, costing the company additional money in order to rectify issues with the new software. In the worst case, the software would not work at all and would need to be replaced.

Hardware and operating system settings

For the purposes of this topic, the diagnostic tests are reasonably simple. There are several basic tools that can be used to determine a computer’s hardware and software configuration.

Example: Windows tools

In a Windows-based computer these tools range from simply using Windows Explorer to get basic information on:

1 free disk space in the status panel

2 storage devices detected

3 network connections

4 the version of the operating system.

There is also a Sysinfo program that has many useful diagnostics, particularly under the System heading, including:

1 free disk space

2 RAM

3 total disk space

4 operating system

5 other useful information regarding versions of currently loaded DLLs, executables running and more complex statistics.

You can find the sysinfo program MSInfo32.exe in the folder at:

c:\Program Files\Common Files\Microsoft Shared\MSInfo\


Application software

The Control Panel, Add/Remove Programs applet indicates programs installed on the computer. Unfortunately this is only useful in the case where programs have registered with the Control Panel applet, so not all installed programs appear in this list. To run the applet, go to the Start menu and select Control Panel (XP), and then double click on the Add/Remove Programs icon.

Sometimes the best way to check if a program is installed correctly is to try running it from the Start menu, or double clicking on the program icon in the Explorer.


Identify and map system interaction

Before you can determine if the new software is suitable to be installed on your network, you will need to research the technical specifications and requirements of the new software. In particular we will be focusing on the data requirements of the new application.

What data is requiredIt is outside the scope of this topic to cover the whole subject of user data requirements, so here we will focus on simple data sharing concepts.

Reflection

Assume that a real estate sales person had a spreadsheet that listed all the possible buyers that they had ever met. Because of an increase in workload a second sales person is to work as an assistant and help with sales. First, think of the disadvantages of making this assistant create and maintain their own spreadsheet.

Second, if they were to share the spreadsheet stored on a server and access it through each of their own PCs, what issues do you think they would have to consider?

Feedback

Disadvantages of creating a second spreadsheet would be:

They may not record exactly the same details.

Buyers may be duplicated in both.

One user may think that the other has a buyer entered when neither do.

It can be difficult to get a total view of buyers.

With one spreadsheet in place they would need to consider:

Can they both access the spreadsheet at the same time?

If adding a new user, will it be seen by the other instantaneously?

What happens when changes are made?

Will the assistant be able to perform the same tasks as the other sales person?


Multi-user data access considerationsMost applications that are designed to be multi-user will have features built into them to overcome some of these issues. It is still important for the administrator to be aware of these issues though especially during the installation and configuration of the application.

It is also possible that applications that are primarily single user are also used across a network and data is to be shared. A good example of this is Microsoft Access.

Activity

Open Excel twice so you have two instances of it running. Try opening the same spreadsheet on each. What message do you get?

Feedback

You should see something like this:

Figure 1: Message received when two users open the same file

Notice that the system will let the second instance open the file but only as a Read Only file. If this user want to save the changes that they have made then they must save the spreadsheet with another name. The problem now is that there are two spreadsheets to maintain.

Two users cannot change the same spreadsheet simultaneously.

While this may be acceptable for a spreadsheet it is not acceptable for a database that is designed to be multi-user. We don’t want to create different databases for each and every user!


Concurrency

One of the first considerations when sharing a database is to allow the same database to be opened in a shared mode. Databases can contain large amounts of data and chances are that two users will not necessarily need to access the exact, same piece of information at the same time.

If users only ever want to read data then there is not much of a problem with concurrency. But if users want to change data then we need to ‘lock’ parts of the database to be only updated by one person at a time.

Reflection

Look back at the message you got with the Excel example, what part of the spreadsheet was locked for update?

Feedback

In this case the whole file was locked.

Reflection

With a database what parts could possibly be locked?

Feedback

In theory a database could be locked at:

the whole database level

a table

a column

a row.

A common approach which allows for a reasonable user access is to lock rows or records. What this means is that two users cannot change the same record at the same time.


Deadlock or ‘deadly embrace’?

While the exact mechanisms for locking data are outside the scope of this topic, this is a well-known issue that you should be aware of. Again, today’s databases do have the capability to overcome this problem but if you ever find yourself in a role where you are writing database access code you may need to consider it.

Imagine that two users are working on the same database.

User A is interested in knowing which products have been sold and user B is interested in customers.

User A looks up Product 1234 and at that moment the 1234 Product record is locked. Meanwhile user B looks up Customer 4567 and that record is locked.

User A sees that Product 1234 was purchased by Customer 4567 and wants to check on their address. When they try to access the record though, it is locked. Their application may wait for the record to become available which will normally happen when user B releases the record.

But user B notices that Customer 4567 bought Product 1234 and wants to confirm what this product was. When they try to access the record though, it is locked. Their application may wait for the record to become available which will normally happen when user A releases the record. But user A is waiting and so will not release their record!

So we now have two applications waiting for the other to release the record and, of course, neither will. The application could hang there forever!

As stated, most multi-user applications and databases have mechanisms for avoiding the above situation, but it can still occur with poor programming.

So, as you prepare for the installation of the application or the database you should ensure that it will work in a multi-user environment and familiarise yourself with the way it handles locking and other concurrency issues.


Examine all existing applications and plan required upgrades or reconfigurations

Network performanceAs you review the upgrade requirements there will be network issues that you will be looking out for. One of the main issues to consider is performance.

Networks may now cover the globe and if you work for an international company you can roam anywhere and still get to your data. With such a large network there will be parts of it that have slower links than others. The quickest is normally a local area network, while wide networks are slower.

When analysing user access to data you need to consider where the user is and where the data is. There may be a third player which is some sort of server that controls what the user sees. Generally speaking though, if the data needs to travel across a part of the network that has a slow link, then performance will suffer. So as network administrator, you should try to keep data and users together on the same high-speed segment.

Reflection

If you can’t bring users and data together, what are your other options?


High Speed LAN

Slow Speed WAN

Feedback

One option is to maintain the status quo and inform users that they may suffer performance problems. They may be prepared to live with these if they are still getting other features and functionality from the application.

Alternatively you may need to consider whether the database or parts of it should be duplicated across the network. Some applications can allow for fault tolerant databases that can be duplicated on two servers. The backup database may then possibly be used to service local users. It may even be possible to copy whole or parts of the database across the network but this would normally only be practical with databases of a limited size.

Other system requirementsSystem requirements ensure that software is installed and run in an appropriate network environment.

All software is designed and developed to operate in a specific computing environment. The appropriate networking environment might consist of both hardware and software components.

Software manufacturers cannot test every combination of computing environment that their software could potentially be installed and run on. To ensure the correct operation of their software, most software manufacturers will specify a precondition to the functioning of their software by recommending a minimum configuration of::

the hardware platform

operating system

server and client resource requirements (CPU, memory)

storage capacity for the software and data

network standards approved

network configurations required.

Note that many software applications specify a minimum disk space and memory to run the application, but require additional resources to install it. Ensure that you also have enough free resources to actually install the product as well as run it.

Many software applications can run in many different network environments, but usually software manufacturers will only guarantee their software in a limited range of network environments. For example many client server systems now require a web browser at the client. While they state that any browser will do, you often find that full functionality is only available when using, say, Internet Explorer.


Activity

List the things that might happen if you run software in an environment that does not meet the minimum system requirements.

Feedback

It is always hard to predict what unexpected things will happen when you run software in the wrong environment but some possibilities are that the software:

does not run at all

runs, but ‘hangs’

behaves in unexpected ways

causes other software applications to behave unexpectedly

hangs your entire system, including the operating system.

Most importantly, if you install software in an environment that does not meet the minimum system requirements, the software manufacturer may refuse to provide product support for the software.

How do I find information about software prerequisites?

The manufacturer of the software always provides software prerequisites.

Here are some ways to find out about software prerequisites:

When you purchase software, a list of prerequisites comes with the product. You should always read this before installing the software on your computer.

Prerequisite information is often found on advertising leaflets or brochures, which you can obtain from the software manufacturer.

Contact your local distributor of the software product, or the product sales/support centre, and they will provide you with the answer over the phone, or send you the appropriate information.

If the software manufacturer has a website which gives details of their products; you will usually find a page which lists the minimum system requirements. Note that some vendors may recommend the minimum requirements for the application to run but to get good performance you may need to have hardware with twice the specification!


System incompatibilitiesSystem incompatibilities are mismatches between the software and the network system configuration. System incompatibilities will prevent the software functioning correctly on the network.

There are times when the minimum system requirements may not be available or not possible to achieve within the existing network. For example, a new customer management system may require a specific database on which to run. Your organisation may have standardised on another database vendor and the new system will not work.

Another example is a program that has been written for a specific operating system. Windows is the most popular operating system but you may want to run in a UNIX or Linux environment.

There may be times when an upgrade of all your systems is required in order to install a new application or a new version of an existing application. This may not be feasible for your organisation in the short to medium term.

During your investigation of minimum system requirements, it is important to recognise those requirements that will make the entire process unfeasible. It is then up to you to suggest that the implementation project be discontinued.

Activity

Assume that the marketing department have selected a new application and you discover that it runs under UNIX and currently your organisation is not using any UNIX servers. Describe the options that are available to the organisation?


Feedback

Options include:

Refusing to install the new application and forcing the marketing department to source a compatible application.

Allowing the marketing department to install their own UNIX machine that is not connected into the main network. This department may then be responsible for its operation and the machine does not form part of the normal network support process.

Installing a UNIX machine in the corporate network. The network group will then take responsibility for maintenance and support. The network policies are amended to allow UNIX to be used and appropriate procedures and staff training are undertaken.

Gap analysis

As you evaluate what the new application requires and compare that with what you have you will identify the missing components that are required to run the application. This is called a gap analysis. It is identifying the components needed to fill the ‘gap’ between an existing system and an ideal/target system.

There is a need for a gap analysis for the servers and the network architecture. For an application that is to go on all desktops then a large organisation may need to perform a gap analysis for each type of desktop computer. The results of the network audit would be grouped together into standard configurations categories based on each distinct combination of hardware and operating system.

Look at the following table. It has been partially completed. It has columns for:

1 standard configurations for actual systems

2 the ideal (target) configuration

3 the gap, which is the difference between the two configurations.


Actual Configuration Ideal Configuration Gap

1. Windows NT 4

2. Internet explorer version 5.0

3. MS SQL Server V7

4. Pentium IV

5. 1 GB RAM

6. 150 GB Free disk space

1. Windows 2003 Server

2. Internet explorer version 5.0

3. MS SQL Server 2000

4. Pentium IV

5. 2 GB RAM

6. 1 GB Free disk space

Activity

Complete the above table by identifying the gap between the actual and ideal systems.

FeedbackGap

1. Upgrade to 2003 Server

2. OK

3. Upgrade to MSSQL 2000

4. OK

5. Add 1 GB RAM

6. OK


Identifying additional resources and installation proceduresNow that we have identified the gap between the existing and target network systems, we can identify resources, which need to be ordered, and steps that need to be included in our installation plan.

Using the gap identified in the previous example:

1 Upgrade to 2003 Server

2 Upgrade to MSSQL 2000

3 Add 1 GB RAM.

We can consider our additional installation procedures.

Activity

For the installation requirements, summarise what needs to be done to the network and what issues you need to consider.

Feedback

You should have identified additional resources such as RAM modules and the two new pieces of software.

Things to consider are:

Will the server physically accept the extra RAM? Adding RAM normally requires no configuration or system settings to be changed and it should have little impact (other than improved performance) on other applications.

What is the impact of an upgrade to Server 2003 and MSSQL? Will this now impact other applications?

Should a big bang or progressive approach be taken? That is, will the upgrade take place over, say, a weekend so when users come back on Monday it is completed?

Should additional servers be put in place with a gradual conversion across?


Test reconfiguration for successful interface with existing system

In reconfiguring a system you can take either a ‘big bang’ approach or implement a progressive change over. Either way you need to think about testing your new configuration. There is no point solving one application’s problems if all the others now fall over!

There is no such thing as a simple change to a system. It is amazing how often what appears to be a simple change ends up taking longer to complete, and then you find that it has impacted other parts of the network which also need changing. Before implementing any change it is essential to ensure that it is fully tested. In this topic we will show you how to plan and complete the test.

So how big is the modification? Is testing a modification to a network similar to testing the whole network? Well yes and no …

We can look at different categories of reconfiguration including:

1 a minor enhancement

2 a major enhancement.

No matter what category the modification falls into, we should always start the testing process by undertaking a simple risk analysis to identify possible levels of failure. So we start by gauging the impact and plan our test process accordingly.

Activity

Describe the impact of the following changes to the day-to-day operation of a network:

1 Adding extra memory to a server.

2 Adding a new router to share the load across web servers.

3 Upgrading to the latest version of a network operating system.

4 Adding a feature that allows reports to be saved as a HTML document and so be available to users on the intranet.


Feedback

You may consider the following levels of failure:

1 Low-level impact — memory increases do not normally cause any issues

2 Low-level of impact — users hopefully will see improved performance

3 High level of impact — this will depend on how different the two versions were, but there may be several new features, changes to the user interface and new ways of operating. Applications will need to be fully tested to ensure compatibility.

4 Low-level impact — there could be other ways to save reports to make them available to users.

Planning the testWith the level of impact in mind it is now time to plan the test. Obviously high impact changes will require a greater degree of planning.

You start by looking at the organisation’s standards and guidelines for testing. There may be a methodology and tools in place that prescribe how to complete defect logs, time logs, result sheets and the like.

Depending upon the type of change you will need to determine the critical areas to test such as database accesses, wide area links, server access, etc.

You should ensure that you have access to all network documentation for the area being tested. You should notify user representatives, operational staff and approval authorities of any scheduled tests. You will need to decide whether to test on a live system or a development system.

Reflection

What are the issues with using a test of the current live system versus a development system?


Feedback

You should have considered:

A development system may not be exactly like a real system especially if performance and load are important issues being tested.

Any problems with the live system will impact users.

Once the testing on the development system has been completed there is still a need to transfer into production. After this has happened the system will still need to be monitored to ensure no problems.

Test system may not have appropriate data.

Part of the system test may be to identify useability issues that do not show up in the development system.

You should ensure the completeness of the test plan by:

checking that all necessary network hardware and software is available

‘walking through’ the plan, checking that it meets project requirements

confirming that all relevant parties are notified of the testing

checking that all documentation and checklists are completed.

Conducting the testOnce the plan is in place you then carry it out!

Preparing the input

You should decide on your approach to testing and determine if you need to use any test data and identify output results associated with that source. You then correlate this information with the related network component sections.

There may be test data still in existence from earlier tests. This may need to be modified for any changes to data base applications or servers. This test data is useful for running against the whole system to ensure that the ‘simple’ change has not corrupted something somewhere else.

Valid and invalid test data will need to be created using existing data or a data generator. Format of the input data will need to be verified and expected results documented.

You also will need to consider the operational area of the organisation for your test activities. You should ensure that all the hardware and software you require is available and scheduled for your use. The entire test plan should be completed by this stage. It needs to be walked through according


to organisational guidelines with all relevant parties. A final check of all documentation and testing tools is completed to ensure that no area requiring testing has been left untested.

Reflection

Can a network ever be fully tested under all circumstances?

Feedback

This is the age-old question. In theory the answer is no but we should be able to test the network enough to be confident that it will work in the most likely combination of events and loads.

Running the testYou run each component of the test and document the results. You should enter details of failures into the defect log if/when they occur. You compare requirements to the test results on the completion of each unit, and complete result sheets.

You summarise and classify results and highlight critical or urgent areas of concern. Then compare results against requirement and design specification. Notify operations of test completion and log attendees’ details/comments and obtain signatures. Then you schedule feedback meeting if necessary. Hopefully all goes well and the test is successful.

Reflection

What if the test is a failure? What should be done?


Feedback

If there are problems with the test then of course the problem should be fixed if possible. After that the test should be run again. The question is how much of the test should be run again? In theory the whole test should be carried out again until it produces successful results.

After the testing is completed you will analyse the results and classify the findings. You will let operations know that the test has been completed and obtain all necessary signatures. Then you will organise a feedback session with managers and interested parties.

Putting into productionYou have a successful test result — now what? Now the modifications can go into production.

You need to complete the test results documentation to the standard required by the organisation. You may have to make modifications to other documentation such as the hardware documentation.

You review the suitability of the system, fulfilment of objectives and suitability to all parties. You review the procedures and documentation used in the system test for use again when implementing subsequent phases.

You may also need to monitor network performance for a while to ensure that there are no problems that will require tuning or modifications.

You obtain client acceptance and sign off and agree and formalise any rescheduled maintenance with all parties.

Reflection

How long after going live should monitoring continue?

Feedback

This will depend upon the scope of the modification. In a major modification it may be prudent to check results for a couple of months to make sure no unforeseen problems occur.


Summary

As a Network Administrator, part of your role will involve working with application developers and database administrators to ensure that their systems and data operate across the network. The reading here covered the way you can identify what is in the network and then how to verify that applications will work and have been correctly configured.

We began with the need to review or audit the existing hardware and software in the network. We then moved on to showing you how to check the data required by users. We looked at the problems associated with concurrent access to shared data on a network and how the use of ‘network aware’ software which can implement file and/or record locking can solve these problems. Then we explored how to plan for any upgrades, and finally test the reconfiguration.

Check your progressNow you should try and do the Practice activities in this topic. If you’ve already tried them, have another go and see if you can improve your responses.

When you feel ready, try the ‘Check your understanding’ activity in the Preview section of this topic. This will help you decide if you’re ready for assessment.


Documents

Identify and document the current system components and ...web1.muirfield-h.schools.nsw.edu.au/technology/resource… · Web viewIn general, the word audit is associated with some