Limiting the speed of HSR [August 2024]

[symon_braunbaer]

Dear Experts,

this question has been asked in the past, but no answer has been provided.
So I am sorry, but I need to ask again: Is it possible to reduce the speed of Hana System Replication
(HSR) as of the Hana version(s) currently available in August 2024. We are afraid, that it may overload the network and cause an outage or at least performance issues for other services.

Many thanks in advance!

[Kishan_D]

Hello,

In addition to the previous response, you may want to check Compression in Replication using HANA parameters global.ini -> [system_replication] -> enable_log_compression and global.ini -> [system_replication] -> enable_data_compression. Note that the activation of the compression reduces the required network bandwidth, but at the same time some additional CPU overhead for compressing and decompressing data and logs.

Also check the number of parallel channels used for data shipping as per https://me.sap.com/notes/1999880#L48. Unnecessary high number of parallel channels can increase network bandwidth usage.

I will also recommend to recheck the selected operation mode for replication as per Data Transferred to the Secondary System | SAP Help Portal. This would also determine the volume send for replication and its impact on network bandwidth usage.

Regards,

Kishan

[dominik_jacobs]

Hi,

as far as I know, SAP HANA System Replication (HSR) ( version August 2024) does not natively provide a direct function to limit or throttle the replication speed. However, there are some strategies you can use to manage and mitigate the network load caused by HSR to avoid performance issues for other services or network.

You can adjust the network QoS settings on your network hardware (routers, switches) to prioritize or limit the bandwidth used by HSR traffic. This requires some effort if the network infrastructure is not centrally controlled. However, it is a common method to avoid overloding the network.

Greetings

Dom