You shouldn’t have any performance problems with that setup for the Archiver Appliance, and you shouldn’t need more appliances unless you are in the 100 000 PV range (on a larger machine).
It’s very hard to debug performance problems, even harder from a distance. Some initial ideas
How fast is the write interface to the var disk
Is the STS on the var disk? Using RAM or the primary disk might help here.
The JVM I believe takes whatever you give it, if you are running out of memory you should reduce what you gave it here. The sampleStartup.sh creates a tomcat per
war file, so that’s 4x whatever memory you changed in the script. Since you have 8GB, probably 1GB is a safe number.
Deployments of the Archiver Appliance unfortunately is still quite site dependent and varied. Something I hope to improve by providing docker containers etc.