Sunday, 25 October 2020

Command Line Parameters for hcmt

Command                          Description 

hcmt -l                               Lists all available tests. 

 hcmt -a

                                          Allows you to specify variables, for example or , without having to wait for prompts by the tool. Sample syntax: hcmt -v -a “DataVolume=/ hana/data,LogVolume=/hana/ log,Hosts=hostname1\,hostname2”



Measure System & Performance - Scale-up Systems

 Pre-requisites:

  • You have installed the latest version of the SAP HANA hardware and cloud measurement tool on the system. 
  • You have at least 20 GB of free storage space in the location where SAP HANA data can be placed during the test. 
  • When using nonvolatile memory, mounts for all hosts or an alias of the same name must be available. 
  • Port 50001 must be open for communication.


The measurement tool performs a series of automated tests based on the execution plan that you select, for example (executionplan.json or full_executionplan.json).


Procedure 
1. To start the measurement tool in verbose mode, enter hcmt -v
2. Adjust the following variables that are contained in the execution plans: 


3. . Enter hcmt -v -p , using the fully qualified path of the installation directory, for example .../installation/config/executionplan.json. 

This starts a measurement using the selected execution plan. The results of the measurement are saved in the hcmtresult-[timestamp].zip file. You can upload the results to the SAP HANA hardware and cloud measurement analysis for a more detailed analysis. For more information, see Analyzing Measurement Results. 


Saturday, 24 October 2020

SAP HANA Hardware and Cloud Measurement Tools for scale out systems

 

SAP HANA hardware and cloud measurement tools help customers and partners to optimize their hardware or cloud systems before deploying SAP HANA.

The measurement results are saved into a single file, which can be uploaded to the SAP HANA hardware and cloud measurement analysis for further analysis and reporting. 


prerequsites:

1. Download the SAP HANA hardware and cloud measurement tool from the SAP Support Portal at https:// launchpad.support.sap.com/#/softwarecenter INSTALLATION & UPGRADES Access downloads Search for: hana optim . 

The download package is displayed: HANA HW CLOUD OPTIM TOOLS 2.0. 

The following versions are available: 

○ LINUX ON POWER LE 64BIT 

○ LINUX ON X86_64 64BIT 

2. Select the version according to your requirements. 

3. Save the download archive in the same directory into which the tool should be installed. 

4. Unpack the archive using SAPCAR. 

5. Install the tool on the system you plan to analyze using hcmtsetup.


How it works:


The SAP HANA hardware and cloud measurement tool performs a series of automated tests, for example network tests, file system consistency tests, system management BIOS tests, and CPU benchmark tests. The duration and repeat rate of the tests depends on the type of execution plan that you intend to run. The following execution plans are available: 

● executionplan.json - Default execution plan that helps you to check if the KPIs for SAP HANA certificDtion are met.

 ● full_executionplan.json - Performs the same tests as the default execution plan, but has a higher test repeat rate and thus a longer test duration. This test is required for SAP HANA certification. 


Measure System Configuration and Performance - Scale-out Systems:

Prerequisites 

● You have installed the latest version of the SAP HANA hardware and cloud measurement tool on the system. 

● You have at least 20 GB of free storage space in the location where SAP HANA data can be placed during the test. 

● When using ROM memory, mounts for all hosts or an alias of the same name must be available.

 ● Ports 50000 and 50001 must be open for communication.  


. For scale-out systems, you start the measurement tool on the master host and specify any worker hosts on which the tests should run as well. The tool reads the execution plan, starts the test locally, and delegates tests marked for scale-out to the worker hosts. The tool waits for the completion of the tests on the worker hosts before starting the next test in the execution plan. All test measurement data and the host manifests are collected in one result file written by the master host instance.

 



Procedure:

1.To start the measurement tool on the worker hosts in verbose mode, enter hcmt -v -S on each of the hosts. 

2. To start the measurement tool on the master host in verbose mode, enter hcmt -v.

 3. Adjust the following variables that are contained in the execution plans:

-----------------------------------------------------------------------------------------------------------------------------

Variable                                                        user entry

-----------------------------------------------------------------------------------------------------------------------------

Log volume                                                  Specify the location where logs should be written. 

Data Volume                                                 Specify an existing location where SAP HANA data can be 

                                                                       placed.

<NvmBasePath>                                            if persistent memory is available, specify mount paths of this persistent memory separated by commas, if no persistent memory is available, leave empty.



4. Enter hcmt -v -p , using the fully qualified path of the installation directory, for example .../installation/config/executionplan.json. 

This starts a measurement using the selected execution plan. The results of the measurement are saved in the hcmtresult-[timestamp].zip file. You can upload the results to the SAP HANA hardware and cloud measurement analysis for a more detailed analysis. For more information, see Analyzing Measurement Results. 

5. End all hcmt processes after finishing the measurement. This helps to ensure that the ports are closed for communication. In particular, remember to close all remote instances, as these may be vulnerable to threats.





Tuesday, 20 October 2020

Concept of swap-in and swap-out

 During normal operation a Linux system tries to keep all application data in physical memory. Linux uses swap-space to store inactive memory pages, evicted from the systems physical memory, in order to free up physical memory capacity. The operation of evicting memory pages from the physical memory to the swapspace is called "swap-out". The operation of restoring pages from the swap-space into the physical memory is called "swap-in".



My Reference:

https://launchpad.support.sap.com/#/notes/1597355

SUSE Linux Enterprise Server 15.x for SAP HANA

 Software required:

The following software was used for the installation:

  • ISO file of SUSE Linux Enterprise 15.
  • Required registration key for the SUSE subscriptions in order to get SUSE maintenance updates.
  • To check the minimum requirements between SUSE and SAP HANA: S-Note - 2235581.


You must have the following information about the host on which you intend to perform the installation: 

● IP address of the host 
● IP alias for SAP HANA (optional) 
● Host name of the host 
● Subnet mask 
● Domain name 
● IP address of the name servers 
● Address of a time server (ntp / chrony) 
● Gateway IP address 
● Proxy IP address and credential (optional) 
● Password for the root user and credential (optional) 
● SAP master password (<sid>adm and sapadm password) 
● SID and instance for the SAP HANA installation 
● UID for the linux user of the system database 
● GID for linux group of the SAP Host Agent



Installation on Intel-based Platform (x86_64)


  • Boot your machine from the SUSE Linux Enterprise media.
 Choose Installation on the boot screen, then press Enter. This boots the system and loads the SUSE Linux Enterprise Server installer


  • Updating the Installer (if internet connection is available)                                                                            
The Installer will receive updates if possible.




  • Language, Keyboard and Product Selection 
○ Choose English as language. 
○ Choose SUSE Linux Enterprise Server for SAP Applications 15.



  • Agree with the License Terms.


 You need to accept the agreement by checking I Agree to the License Terms to install SUSE Linux Enterprise Server for SAP Applications 15. Proceed with Next. 

  • After booting into the installation, the installation routine is set up. During this setup, an attempt to configure at least one network interface with DHCP is made. In case this attempt fails, the Network Settings dialog launches. 




    • Choose a network interface from the list and click Edit to change its settings. Use the tabs to configure DNS and routing.

    • When you are done with the network settings, choose Next to proceed or return to the Registration screen. After at least one network interface has been configured you can register your system at the SUSE Customer Center (SCC). 

    • Enter the e-mail address associated with your SCC account and the registration code for SUSE Linux Enterprise Server. A successful registration is a prerequisite for getting product updates and being entitled to technical support. 



    • If SUSE Linux Enterprise Server for SAP Applications has been successfully registered at the SUSE Customer Center, you are asked whether to install the latest available online updates during the installation. If choosing Yes, the system will be installed with the most current packages without having to apply the updates after installation. Activating this option is recommended. If you have successfully registered your system in the previous step, a list of available modules and extensions based on SUSE Linux Enterprise Server is shown. 




    • Add the Legacy Module in order to be able to install for example libopenssl1_0_0. 
    Other interesting modules you may need, depending on your usage of the system, are:
     ○ SUSE Linux Enterprise Live Patching 15 (adds support for performing critical patching) 
    ○ Development Tools Module 15 (contains compilers like gcc) 
    ○ If you use SAP HANA in the public clouds, the Public Cloud Module 15
     Choose Next to proceed with the installation workflow.





    • After all extensions and modules are registered the next step is available. The installation of Add On Product’s can be prepared if needed. Proceed with Next. 

    • Choose Next for the System Role selection.

    • Choose the default SLES for SAP Applications and choose Next. This option is the preferred and the recommended installation. 


    check the checkbox for Enable remote Desktop protocol(RDP) service and open port in firewall option,  go continue with Next.




    Sunday, 18 October 2020

    Supporting Operating system for HANA

     

    Red Hat for HANA 1.0



    SUSE for HANA1.0



    Red Hat for HANA2.0


    SUSE for HANA2.0




    2235581 - SAP HANA: Supported Operating Systems

     Symptom

    You want to know which operating system versions are supported for SAP HANA.

    Other Terms

    HANA, DB, BW on HANA, RHEL, RHEL for SAP Solutions, SLES, SLES for SAP Applications

    Reason and Prerequisites

    A new operating system version might require a certain HANA Service Pack Stack (SPS) revision in order to be supported.

    Solution

    For better readability of this SAP Note - if not mentioned explicitly otherwise - "RHEL" is used as a synonym for "Red Hat Enterprise Linux for SAP HANA" (RHEL for SAP HANA) and "Red Hat Enterprise Linux for SAP Solutions" (RHEL for SAP Solutions).
    Furthermore "SLES" is used as a synonym for "SUSE Linux Enterprise Server" (SLES) and "SUSE Linux Enterprise Server for SAP Applications" (SLES for SAP Applications).

    NOTE: The attached PDF file outlines which combinations of RHEL Minor Releases or SLES Support Packages are supported with the various SAP HANA versions.
    Consider RHEL Minor Releases or SLES Support Packages not explicitly listed in this SAP Note and the attached PDF file as not supported.
    At minimum the specified HANA Service Pack Stack (SPS) revision needs to be used when running the given OS version. This includes newer revisions within the specified SPS as well as newer Service Pack Stacks within the specified HANA version.

    Check the information in the related SAP Notes and other information sources. This SAP Note only refers to technical information in other information sources and is not the origin of this information. The purpose of this SAP Note is to provide an overview of already existing information sources. This SAP Note will be updated regularly.

    SAP Certified Hardware for SAP HANA

    Hardware that has been certified within the SAP HANA hardware certification program has been certified on a specific operating system version. The Hardware Directory shows the supported combinations of hardware and operating system. This approach applies to both appliance and TDI. Certified hardware exists for the operating system versions mentioned below.

    For more information, see the Certified and Supported SAP HANA® Hardware Directory and SAP Note 1943937 Hardware Configuration Check Tool - Central Note.

    Supported Operating Systems for SAP HANA

    One of the following Enterprise Linux distribution products, in the below-mentioned version, is required for running SAP HANA:

    • Red Hat Enterprise Linux for SAP Solutions
    • Red Hat Enterprise Linux for SAP HANA
    • SUSE Linux Enterprise Server for SAP Applications
    • SUSE Linux Enterprise Server

    SAP strongly recommends to use "RHEL for SAP Solutions" or "SLES for SAP Applications" due to their features and extended support cycles. For detailed information about the Linux product flavors, their feature set and benefits, please contact your respective Linux sales representative.

    Supported Operating Systems for SAP HANA 1.0 on Intel-Based Hardware Platforms

    For running an SAP HANA 1.0 system on Intel-based hardware platforms the following operating systems are supported:

    • Red Hat
      For general information how to configure Red Hat for SAP HANA, see the configuration guides attached to SAP Note 2009879.
      • RHEL 7 for SAP Solutions / RHEL 7 for SAP HANA - consult SAP Note 2292690 for recommended OS settings
        • 7.7 (HANA 1.0 SPS12 revision 122.30 and newer)
        • 7.6 (HANA 1.0 SPS12 revision 122.23 and newer)
        • 7.5 (HANA 1.0 SPS12 revision 122.19 and newer)
        • 7.4 (HANA 1.0 SPS12 revision 122.14 and newer)
        • 7.3 (HANA 1.0 SPS12)
        • 7.2 (HANA 1.0 SPS12)

      • RHEL 6 for SAP Solutions / RHEL 6 for SAP HANA
        • 6.10 (HANA 1.0 SPS12 revision 122.23 and newer, consult SAP Note 2694292 for recommended OS settings)
        • 6.7 (HANA 1.0 SPS11 and newer, consult SAP Note 2247020 for recommended OS settings)
        • 6.6 (up to HANA 1.0 SPS11, consult SAP Note 2136965 for recommended OS settings)
        • 6.5 (up to HANA 1.0 SPS11, consult SAP Note 2013638 for recommended OS settings)

    • SUSE
      For general information how to configure SUSE for SAP HANA, see the configuration guides attached to SAP Note 1944799.
      • SLES for SAP Applications 15 / SLES 15 - consult SAP Note - 2684254 for recommended OS settings
        • 15 SP1 (HANA 1.0 SPS12 revision 122.27 and newer)
        • 15 (GA) (HANA 1.0 SPS12 revision 122.21 and newer)

      • SLES for SAP Applications 12 / SLES 12 - consult SAP Note - 2205917 for recommended OS settings
        • 12 SP5 (HANA 1.0 SPS12 revision 122.29 and newer)
        • 12 SP4 (HANA 1.0 SPS12 revision 122.22 and newer)
        • 12 SP3 (HANA 1.0 SPS12 revision 122.15 and newer)
        • 12 SP2 (HANA 1.0 SPS12)
        • 12 SP1 (HANA 1.0 SPS12)
        • 12 (GA) (HANA 1.0 SPS10 and newer)

      • SLES for SAP Applications 11 / SLES 11
        • 11 SP4 (HANA 1.0 SPS10 and newer, consult SAP Note 2240716 for recommended OS settings)
        • 11 SP3 (HANA 1.0 SPS10 and newer, consult SAP Note 1954788 for recommended OS settings)
        • 11 SP2 (up to HANA 1.0 SPS11, consult SAP Note 1824819 for recommended OS settings)

    Supported Operating Systems for SAP HANA 1.0 on IBM Power Servers

    For running an SAP HANA 1.0 system on IBM Power servers the following operating system is supported:

    • SUSE
      For general information how to configure SUSE for SAP HANA, see the configuration guides attached to SAP Note 1944799.

    Supported Operating Systems for SAP HANA 2.0 on Intel-Based Hardware Platforms

    For running a SAP HANA 2.0 system on Intel-based hardware platforms the following operating systems are supported:

    • Red Hat
      For general information how to configure Red Hat for SAP HANA, see the configuration guides attached to SAP Note 2009879.
      • RHEL 8 for SAP Solutions / RHEL 8 for SAP HANA - consult SAP Note 2777782 for recommended OS settings
        • 8.1 (HANA 2.0 SPS04 revision 45 and newer)
        • 8.0 (HANA 2.0 SPS04 only, starting with revision 40)

      • RHEL 7 for SAP Solutions / RHEL 7 for SAP HANA - consult SAP Note 2292690 for recommended OS settings
        • 7.7 (HANA 2.0 SPS04 revision 48 and newer, HANA 2.0 SPS05 and newer)
        • 7.6 (HANA 2.0 SPS03 revision 36 and newer)
        • 7.5 (HANA 2.0 SPS03 only, starting with revision 32)
        • 7.4 (HANA 2.0 SPS02 revision 23 and newer, up to HANA 2.0 SPS04)
        • 7.3 (HANA 2.0 SPS02 revision 21 and newer, up to HANA 2.0 SPS03)
        • 7.2 (up to HANA 2.0 SPS03)

    • SUSE
      For general information how to configure SLES for SAP HANA, see the SLES configuration guides attached to SAP Note 1944799.
      • SLES for SAP Applications 15 / SLES 15 - consult SAP Note 2684254 for recommended OS settings
        • 15 SP1 (HANA 2.0 SPS04 revision 44 and newer)
        • 15 (GA) (HANA 2.0 SPS03 revision 34 and newer)

      • SLES for SAP Applications 12 / SLES 12 - consult SAP Note 2205917 for recommended OS settings
        • 12 SP5 (HANA 2.0 SPS04 revision 45 and newer)
        • 12 SP4 (HANA 2.0 SPS03 revision 35 and newer)
        • 12 SP3 (HANA 2.0 SPS02 revision 23 and newer, up to HANA 2.0 SPS04)
        • 12 SP2 (HANA 2.0 SPS01 and newer, up to HANA 2.0 SPS03)
        • 12 SP1 (HANA 2.0 SPS00 and newer, up to HANA 2.0 SPS03)

    Supported Operating Systems for SAP HANA 2.0 on IBM Power Servers

    For running an SAP HANA 2.0 system on IBM Power servers the following operating systems are supported:

    • Red Hat
      For general information how to configure Red Hat for SAP HANA, see the configuration guides attached to SAP Note 2009879.
      • RHEL 8 for SAP Solutions / RHEL 8 for SAP HANA - consult SAP Note 2777782 for recommended OS settings and SAP Note 2055470 for supported processor generations.
        • 8.1 (HANA 2.0 SPS04 revision 45 and newer)
        • 8.0 (HANA 2.0 SPS04 only, starting with revision 45)

      •  RHEL 7 for SAP Solutions / RHEL 7 for SAP HANA - consult SAP Note 2292690 for recommended OS settings and SAP Note 2055470 for supported processor generations.
        • 7.7 (HANA 2.0 SPS04 revision 48 and newer, HANA 2.0 SPS05 and newer)
        • 7.6 (HANA 2.0 SPS03 revision 36 and newer)
        • 7.5 (HANA 2.0 SPS03 only, starting with revision 32)
        • 7.4 (HANA 2.0 SPS02 revision 23 and newer, up to HANA 2.0 SPS04)
        • 7.3 (HANA 2.0 SPS02 revision 21 and newer, up to HANA 2.0 SPS03)

    • SUSE
      For general information how to configure SUSE for SAP HANA, see the configuration guides attached to SAP Note 1944799.
      • SLES for SAP Applications 15 / SLES 15 - consult SAP Note 2684254 for recommended OS settings
        • 15 SP1 (HANA 2.0 SPS04 revision 44 and newer)
        • 15 (GA) (HANA 2.0 SPS03 revision 34 and newer)

      • SLES for SAP Applications 12 / SLES 12 - consult SAP Note 2205917 for recommended OS settings
        • 12 SP5 (HANA 2.0 SPS04 revision 45 and newer)
        • 12 SP4 (HANA 2.0 SPS03 revision 35 and newer)
        • 12 SP3 (HANA 2.0 SPS02 revision 23 and newer, up to HANA 2.0 SPS04)
        • 12 SP2 (HANA 2.0 SPS02 and newer, up to HANA 2.0 SPS03)
        • 12 SP1 (HANA 2.0 SPS00 and newer, up to HANA 2.0 SPS03)

    Conversion of HANA DB from single container to combination of system DB and tenant DB.


     The system can be installed on one or multiple system hosts, which are configured to operate as worker or standby hosts. As of SAP HANA 2.0 Support Package Stack (SPS) 01, the SAP HANA system can only be installed or configured to be a tenant database system. A tenant database system contains one system database and can contain multiple tenant databases. A single-container system will be automatically converted to a tenant database system during the upgrade to SPS 01.


    Saturday, 17 October 2020

    Software Authenticity Verification

     An SAP HANA system can be installed using the SAP HANA database lifecycle manager (HDBLCM). Since the installation software is downloaded from outside your network, it cannot be trusted. Therefore, you should first make sure that the components are authentic, before starting the SAP HANA database lifecycle manager (HDBLCM). 

    To verify the authenticity of a SAR archive, use the following command:

     /usr/sap/hostctrl/exe/SAPCAR -dVf /usr/sap/hostctrl/exe/ libsapcrypto.so 

    To verify the signature the additional components, run hdblcm with the parameter verify_signature. For more information, see SAP Note 2577617. 


    •  the authenticity verification is only enabled by default if the SAP HANA database was installed or updated with an authentic signature. The signature file is located under <inst_path>/<SID>/hdblcm/SIGNATURE.SMF).
    •  If you are not sure whether the SAP HANA system was installed with a valid signature, you can run the SAP HANA resident HDBLCM with the parameter verify_signature. 

    Navigation for SAP HANA software and Support Packages and Patches for SAP HANA in market place

     

    • The SAP HANA database lifecycle manager is used to install either individual or multiple SAP HANA components in combination with the server.
    • The SAP HANA database lifecycle manager offers three user interfaces: - a graphical user interface, a command-line interface and a Web user interface.
    • Before starting the installation of SAP HANA, make sure that you have reviewed the SAP HANA Master Guide.

     

    ***Caution***

    It is essential to keep a copy of all installation media which may be required, for example, for disaster recovery purposes. Installation media which has been superseded is routinely removed from the Software Center and there is no guarantee that all database revisions will be permanently available.

     

    Installation Media for an SAP HANA SPS

    1. Open the SAP Software Downloads.

    2. Go to INSTALLATIONS & UPGRADES, if not already chosen.

    3. Open > By Alphabetical Index (A-Z).

    4. Choose H.

    5. Choose SAP HANA PLATFORM EDITION.

    6. Go to DOWNLOADS tab, if not already opened.

    7. Choose SAP HANA PLATFORM EDITION 2.0.

    8. Open DOWNLOADS tab, if not already opened.

    9. Choose INSTALLATION.

    10. select the required files and Add to download basket.

    11.Download the items you need.

     

     

    Support Packages and Patches for SAP HANA

    1. Open the SAP Software Downloads.

    2. Choose SUPPORT PACKAGES & PATCHES, if not already chosen.

    3. Open > By Alphabetical Index (A-Z).

    4. Choose H.

    5. Choose SAP HANA PLATFORM EDITION.

    6. Choose DOWNLOADS, if not already chosen.

    7. Choose SAP HANA PLATFORM EDITION 2.0.

    8. Choose DOWNLOADS, if not already chosen.

    9. Open the required component and download the items you need.

     

    *Note :The items you have downloaded must be available on the host where the SAP HANA system will be installed or is already installed.



    Relational Databases and Non relational databases

     Relational database: A relational database is one that stores data in tables. The relationship between each data point is clear and searching through those relationships is relatively easy. The relationship between tables and field types is called a schema. For relational databases, the schema must be clearly defined.

    Eg: MS SQL,My SQL, Postgre SQL.


    Non - Relational Databases: A non- relation database that does not use the tabular schema of rows and columns like in relational databases. Rather, its storage model is optimized for the type of data it's storing.

    eg: NoSQL


    Reference:

    https://www.izenda.com/relational-vs-non-relational-databases/

    Monday, 12 October 2020

    EC2 Dedicated host

     * You reserve an entire host on AWS cloud and you launch EC2 instances directly on it.

    * it can help in a BYOL(bring your Own license) model or when you have strong regulatory, compliance or security requirements.

    * it's overall more expensive and should not use it unless strongly required. you can also reserve dedicated hosts.


    Hands for launching dedicated host:

    Navigate to instances --> Dedicated Hosts


    Click on Allocate a host, as shown below.                                                                                               


    provide details:

    1. choose instance type for dedicated host.
    2. Available zone for the dedicated host.
    3. allow instance auto-placement - basically an auto scale of dedicated EC2 instance option.
    4. quality of dedicated EC2 instance.
    5. finally click on Allocate host as highlighted below.



    3rd party spot instance providers

     1.Spotinst (claiming to have 80% cost reduction of EC2 instance for 100% avaialability)

    2. Qubole (to run big data jobs on spot instance).


    Spot instance

     AWS EC2 spot instances  are using the spare capacity in AWS cloud and provide you EC2 instance at individual requested price.

     At any point of time,AWS can reclaim(terminate ) your instance to the highest bidder with 2 minutes of notification.

    you can use AWS EC2 spot instance for machine critical appications.

    Do not run critical jobs on EC2 if you can't tolerate failure!.


    Hands on:

    from the EC2 instance launch page, Navigate to instances --> Spot Requests from the left menu.


    Click on Request spot instances.                                                                                                                     

    Then the screen prompts to screen where we need to provide all the inputs for spot instance. provide all your inputs based on your requirements.

    Finally click on launch.  










    Saturday, 10 October 2020

    SAP_R3_ARCHITURE

     

    SAP Architecture is defined as a technology framework of SAP system and it changes with time from software version to version.

    SAP Architecture changes with new software like SAP ECC 6.0, the most recent one.

     

    Database: collection of data in organized tables. With database can do

                                                                                       storage of data in tables.

                                                                                        creation of new tables

                                                                                        Accessed data

                                                                                        Modification of new tables/data

                                                                                        Delete of tables/data.

    Application server: where all the logic of code resides.

     

    Presentation layer: frontend for Application layer.



    -----------------------------------------------------------------------------------------------------------------------------







    Drawbacks:
                                                                                                                                                       
    There is No Q- mechanism.                                                                                               


    R/3 Client/Server Architecture:                                                                                                           

                   
                                                                                                         


                                                                Fig: Single Application server architecture.            

     Buffer it will store frequently access data and rarely modified data.

    suppose based on the RAM( buffer) size in application server, it can  store 100 recent requests, say like RAM size is 8 GiB.

    when the complete new request came from end user say 101 request, Buffers will automatically delete 1 st request in 100 requests and include this 101 request in to the 100 request back.So the buffer memory is filled with 100 requests again.

     

    Dual stack Application architeuture:










     

    Step 1) Once a user clicks on the SAP system from GUI, the user request is forwarded to Dispatcher.
    Step 2) Request is stored in Request queues first. Dispatcher follows First in First out rule. It will find free work process and if available will be assigned.

    Step 3) As per user request, particular work process is assigned to user. For example, when user login to the system then Dialog work process is assigned to the user. If user runs a report in background then background work process is assigned to the user.When some modifications are done at database level then update workprocess is assigned.So as per user's action work process is assigned.

     

    Work processor: 16

    dialog wp – 10
    background work process – 3
    spool workprocess – 1 – print

    Update 1 – 1 – data base update
    update 2 – 1 – statics of update wp 1
    à like percentage the update work process1  done(ex:10---20 %)




    Step 4) Once user is assigned the dialog workprocess then user authorizations, user's current setting are rolled in to work-process in shared memory to access user's data.  Once dialog step is executed then user's data is rolled out from workprocess. Thus shared memory will be cleaned and other user's data can be saved in shared memory area. Dialog step means the screen movements. In a transaction, when a users jumps from one screen to other the process is called a dialog step.

    Step 5) First work process will find the data in the buffer. If it finds data in buffer then there is no need to retrieve data from database. Thus response time is improved and this process is called Buffer hit. If it does not find the data in buffer then it will find the data in database and this process is called miss. Hit ratio should be always higher than miss ratio. It improves the performance of system .

    Step 6) Other requested data is queried from the database and once the process is complete,the result is sent back to GUI via dispatcher.

    Step 7) At the end user's data is removed from shared memory so the memory will be available to other users.This process is called roll-out.



    Message server functionality:




    Message server – purpose of message server is to load balancer the user traffic.                

     

     

    1 st request for 1 st application  - 10: 00 AM

    2nd request for 2nd application

    in case of 500 requests    – 250 requsts 1st application server
                                                250 requsts 2nd application server

     

    SAP landscape:


    DEV – DB               - laptop 1
    DEV  - Applicatioon   - laptop 2
    DEV – Presentation .

    Quality – DB              - Laptop 3
    Quality – Appplication – Laptop 4
    Quality - presentation layer


    Production – DB                - laptop 5
    Production – Appplication   - laptop 6
    production presentation layer