Let's Talk SAP

So this is more about ports and communication with respect to a ABAP NETWEAVER SETUP and these are pretty basic things that we would be discussing. This is for complete beginners who have no clue about networking. As a BASIS Consultant you will encounter this multiple times in your life that you need to raise a ticket to your OS Team or SM Team to assign a port to a service or to open a port. Ever wondered what this port is and what is its need ? Do this before reading forward ,  Open command prompt in your windows as an administrator and get result of netstat -ab , you will get a list like this (Google your option if using any other user) I highlighted the port number, things that comes after the IP, you can notice that we have the same IP and different port numbers for different services . Understand this like IP is your building (SAP SYSTEM) with multiple flats in which different flats , different services reside.  Let's understand using this figure : (Click on Image) Service Po

Hey Folks! Welcome back to Hana high availability blog series. In our last blog we checked out what is hana system replication and how it basically works. If you haven't gone through that blog, you can checkout link In this blog we will be talking about the replication modes and operation modes in hana system replication. So let's get started. When we setup the replication and register the secondary site, we need to decide the operation mode & replication mode we want to choose for replication. For now we won't focus on setting up replication as we'll cover it in our next blogs.  Operation Modes in Hana System Replication: There are three operation modes available in system replication: delta_datashipping, logreplay and logreplay_readaccess. Default operation mode is logreplay. 1. Delta_datashipping: In this operation mode initially one full data shipping is done as part of replication setup and then a delta data shipping takes place occasionally in addition to cont

In our last blog, we saw what actually is high availability in context of SAP. If you haven't checked it out yet, you can go through this link . In this blog, we will specifically talk about Hana System replication concept. What is System Replication? As we checked, it's a way to achieve high availability in case of outage due to planned maintenance, faults and disasters. It has a very low RTO of few minutes and a RPO of 0 seconds. RTO - Recovery Time Objective is the time taken to make the secondary/standby system available after the failure of primary system. RPO - Recovery Point Objective is the difference between the timestamp at which the primary system failed and the timestamp of the latest replicated logs/data available on secondary system. System replication is supported in every hana installation and can be used for HA as well as DR scenarios.  It is configured as exact copy of the primary system with same number of worker nodes. We can setup multitier system as well

When we talk about high availability, we mostly think it's just the hana system replication. But, this is not the right statement, especially in case of SAP Hana. To know the reason, let's get into the concept of high availability. High availability is a method or a set of techniques that allows us achieve business continuity. This basically means that the system should be available continuously to run the business. SAP HANA is designed in such a way that it properly supports high availability. It can help us prevent our system from faults, software errors & disasters. Following are the high level concepts that help us achieve high availability in SAP:  Fault tolerance - It is the ability of a system to suffer a fault but continue to operate. It eliminates single points of failure. Fault resilience - It is the ability to recover quickly from an outage Fault recovery - It is the process of recovering and resuming operations after an outage due to a fault Disaster recovery

How many times you have created a new client and then in order to login you had to unlock sap* for which you needed a restart ? Guess what SAP heard you, SAP delivers new client management tools based on new common architecture . The new client copy is complete redesign and replace the old client copy with added new features. The new process are optimized for increased performance, process automation, stability and the client export and client import have been expanded to include the option of exporting / importing “SNAPSHOTS”. The new client added feature is added from SAP_BASIS 7.54 (SAP S/4HANA 1909).New tools to compare clients and determine the size of client is added from SAP_BASIS 7.55. With SAP_BASIS 7.55 Service Pack 1, transaction SCC1 is finally moved to the new architecture. What’s new in this Client Copy ? How does new client copy has helped to increase the stability ? It is no longer necessary to start the client copy in the target client. Instead, this can now be started

 You just need to login to a hdbsql with a user which has USER_ADMIN privilege's  and use the following :- -- Deactivating user ALTER USER < user_name > DEACTIVATE USER NOW ; -- Activating user ALTER USER < user_name > ACTIVATE USER NOW ;

This blog is for beginner in HANA savepoint , if you know already how it works feel free to skip this blog and read another blog mentioned as Advanced Hana Savepoint. I have used a reference from Klaus in this blog and you can check his blog in link. We all know, that the unique selling point of HANA is that it is in-memory database, which means that the data is stored and processed in RAM. First thing that popped in my mind after hearing this was, If it is stored in RAM what happens when you turn off the system. As RAM is volatile in nature, how is persistency maintained ? So when persistency is concerned , SAVEPOINTS come in action. Savepoints are required to synchronize change in memory with disk level data . Savepoint is a periodic point in time , when all changed data is written in storage in form of pages, all data is flushed from memory to data volumes.  Talking in Layman terms, how the data is saved from RAM to disk, which is a nonvolatile storage . How HANA as a database justi