Memory usage is high after upgrading to after 20.4 Junos version

- EX4300, EX4600 & QFX5100

- Increase in number of CLI sessions or JWEB sessions.

- Upgrade to 20.4 or later

There is increase in memory footprint across different daemons after an image upgrade resulting increase in the system memory. This is due to software architecture change in 20.4 which led to the increase in memory usage for some of the daemons.  

Example: - After upgrade to 20.4 with 7 CLI sessions open, the memory utilization is high

root> show system memory 

fpc0:

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

System memory usage distribution:

    Total memory: 1943552 Kbytes (100%)

  Reserved memory:  38572 Kbytes ( 1%)

    Wired memory: 156056 Kbytes ( 8%)

   Active memory: 1427928 Kbytes ( 73%)

  Inactive memory: 163184 Kbytes ( 8%)

    Cache memory:  55888 Kbytes ( 2%)

    Free memory: 101216 Kbytes ( 5%)

If the system memory consumption beyond 80%, system will generate the below alarm.

/kernel: Percentage memory available(19)less than threshold(20 %)- 1

Customer is advised to reduce the number of open CLI sessions which can reduce the unnecessary system memory consumption.

Note:

In this log, inactive memory is also considered as used hence always check "show chassis routing-engine" for actual DRAM utilization.

https://prsearch.juniper.net/problemreport/PR1694522