Have you tried checking if the question is about headroom or actual tested limits? 128MB sounds tight but OpenVPN itself can run in less. The real killer is TLS handshake bursts and concurrent connections. I feel you if youre coming from a support background where users swear 128MB is plenty because some blog said so.
Anyway I tried this at 3am last week on a 128MB CloudCone box https://cloudcone.com idk why I do this
openvpn --config server.conf --mlock 
Pro tip: Oracle Cloud free tier gives you 1GB ARM instances, not 128MB. Heads up, this is a solved problem with better resources. But if you must:
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Tls handshake eat all memory. Network not stable after OOM. I try on KnownHost 128MB plan, always crash. Better get 256MB minimum. Сервер need more RAM.
Can or not? 128MB already enough for openvpn lah, but must configure properly dong. My friend use 128MB at Time4VPS, no problem one. But he only have 3 users, not many. If many users, need more RAM lah.
Openvpn use memory too much,not possible lah. I go already to 256MB plan,working better. Dont waste time lah.
I tried 128MB for my shop remote access. Constant OOM kills, my customers angry. As a small business owner I learned cheap cost more in downtime. 'Saras Crafts'
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Oracle Cloud free tier still has that weird registration wall though.
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Same here, 128MB is a joke for tls handshakes. I tried.
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This matches what I saw on a InterServer 256MB box last year, except OpenVPN survived but the handshake took 11 seconds. Client timed out before auth finished.
128MB is not about whether the daemon starts. It's whether the handshake completes before the client retries and spins up another worker.
Has anyone actually measured wolfSSL memory use versus OpenSSL in practice? The savings look good on paper but I never got around to swapping the library.