Recommended hardware requirements / minimum system requirements for Stalwart mail-server

[mamiu]

I'm curious what the recommended hardware requirements for the Stalwart mail-server are. Couldn't find it in the docs.

I know this depends a lot on the load of the system and the specific use case, but I'd love to see a generic recommendation with examples how to calculate the necessary hardware resources different use cases.

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There's already a discussion (#558) but it's closed and has no satisfying answer to the question. Also, this question is keyword optimized, because I couldn't find anything when performing a Google search.

[mdecimus]

For a small setup you can start with any VPS with 1GB or RAM. Stalwart has low memory requirements so this would vary based on the number of concurrent users you have.

[mamiu]

Thanks @mdecimus. I'll probably have around a 100 concurrent users sending probably 30-50 emails per day, so Stalwart had to process about 3k-5k emails per day in total.

[mamiu]

I just installed the Stalwart mail-server with Docker on a VPS with 4 vCPUs and 6 GB of RAM.
(The performance of docker containers is nearly identical to native performance.)

I haven't configured anything yet. It's just the default setup.

So far the this instance uses 122 MiB (about 128 Megabytes) of memory and consistently 0% of the CPU.

I'll update this response as soon as I've set up some domains and mailboxes (accounts).

So far this is the best performing mail server I've ever seen/tried/used!
Congrats and thank you so much to the team (@mdecimus)! Stalwart is awesome! 🎉

[HansG9]

any update on which system requirements you would recommend after using stalwart? @mamiu

[mamiu]

@HansG9 Stalwart is so resource efficient, that you can literally run it on everything that has 512MB memory or more... even an old Raspberry Pi is more than enough.

[andreymal]

122 MiB

Now I'm curious why a fresh Stalwart installation on my PC uses 188 MiB of memory, I haven't even created any accounts yet...

My current "classic" Postfix+Dovecot+OpenDKIM installation uses 64 MiB of memory, so compared with it, I would consider Stalwart resource-heavy

[jjj333-p]

odd, it only uses 12mb of ram on my system

[andreymal]

Hmm, when running in VirtualBox instead of Docker, Stalwart only uses 100 MiB of memory

(12mb would be great but I have no idea how to achieve this)

[jjj333-p]

12mb is almost implausibly light so i do wonder if btop is just measuring it incorrectly