When SQL server is installed on Linux platform, memory.memorylimitmb config setting will limit SQL Server to use 80% of the available physical RAM by default.

for example,

Total Memory on Linux Host: 10GB
Max Memory on SQL Server: 8GB
Memory reserved for OS: 2GB

In case, we want to increase SQL Server max memory by another 1GB, then just increasing SQL Server max memory value will not help picking up updated memory, memorylimitmb OS setting also need to changed for actual memory to reflect on SQL server and this will require SQL server reboot.

currently memorylimitmb value is set to 8000 and we want to change it to 9000

[memory]
memorylimitmb = 8000

• Setting the memory limit to 9000 MB:

sudo /opt/mssql/bin/mssql-conf set memory.memorylimitmb 9000

• Restart the SQL Server service to apply the changes:

sudo systemctl restart mssql-server