Problem
A UCS system gets very slow and sluggish after a while. Services do not reply in a timely manner and the memory usage is high. After a reboot the server acts fine and speedy again.
Environment
To make sure the issue is memory related monitor memory management in UCS with the tool free and watch.
root@ucs:~# watch -n 60 free -m
Every 60,0s: free -m ucs: Mon Oct 8 12:25:58 2018
total used free shared buff/cache available
Mem: 4963 452 688 19 3822 4204
Swap: 4959 272 4687
If the “used” value of Swap changes frequently and the swap is used more than approximately 30% you might have to few memory for your system.
Solution
Add more memory to the system or reduce the amount of services running on this host.