Thank you for all your answers and sorry to be late for answering.
> I prefer ZFS but I find that lots of corps prefer mdadm. I really think that's simply > because ZFS came from Sun and they lack Solaris backgrounds. Now, in a low-> RAM environment with simpler disc needs, I would probably go with mdadm.
> Anything else I would choose ZFS. It's ability to take care of itself is surprisingly > strong. Less work for me after the set up and installation.
ZFS beeing a filesystem and mdadm an utility software, I think I'll go for mdadm. I didn't know that Debian was supporting ZFS I always used Ext4.
> Well, this might be heresy, but at that size, consider a Raspberry Pi running Raspian
> I use a 3+ because I want to give the 4 a couple years to get its hardware and software debugged.
I already have some raspberry pi running at home and even if I found they can do very many things, they don't match what I want now. I'm currently using the 4b model with 1Gb of RAM which seemed to have enough power for doing much more things but it's not yet able to boot from an external hard drive, but I tried hacking this with fstab and it worked sometimes and not on the next boot, so I just stopped trying to figure out what happened. I dislike the idea that if I encrypt my hard drive anybody with enough knowledge can just take the SD card and break my encryption.
> I think Debian is a very good choice for a small enterprise server.
> ...
> I have been burned more than once with hardware RAID solutions.
Sorry if I'm misunderstanding, are you saying that Debian cannot scale in a bigger enterprise ?
Can you tell me what happened with hardware RAID solutions?
> small" could be anything from 10 to 1000 users. Mentioning some numbers
> could get you more useful recommendations.> In any case, some interesting hardware not mentioned so far (don't> forget about the power consumption).
Small here is for me about 2000 users all are restaurants that save their selling history locally on their own server then 2 or 3 times in the morning they will rsync their postgres data on my data center.
About the power consumption, any advice about some low power hardware are also welcome.
> Supermicro 1U servers - run two or more of them
> and it's easy to turn them into a high-available cluster> ...
> Note: I'm seriously considering migrating from Debian for our
> next refresh - I really don't like systemd - might go all the way to BSD>or an OpenSolaris distro.
>> First of all, please don't ask me why I simply don't want to use aws or gcp.> Even if you do not use their services, you might find it useful to
> emulate them and implement a private cloud.
Very interesting, can you tell me more about that emulation process please ?
> Please specify the architecture of your services, your current
> development/ test/ staging/ production infrastructure and facilities,
> your current workload for each service, your current quality of service
> for each service, and all other relevant details.
> Please describe your goals for the new data center in terms of the above.
I don't really know how to answer to your question but let's try. We are a startup and for the moment we have a production and a development, in fact the production is just like a test environment because we do continuous delivery, we push everyday in order to know more quickly when something has been broken and our semi-automated tests didn't detect it. Personally, I'm a self learner, and probably many guys of my team are too. So some advices here are also welcome.
We want to be able to handle 2500+ rsync in the morning (probably distributing them in time in order to avoid a single big load acting as a ddos) and for each client of my clients (restaurants) a get and put profile request.
Note: client's profile are shared across restaurants and clients can find/filter restaurants on the website which is not yet built but we are working on it.