I also own the ODROID-HC2 for exploring CEPH.
https://docs.ceph.com/docs/jewel/start/ ... endations/
The Limiations of the ODROID-HC2 is the memory an the Ethernet connections.
When using Ceph in a high availability environment you should use redundant bounded Ethernet connections to two Switches so your OSD is accessible even if one switch fails.
This can be done by using LACP on IRF able HP Switches or may be on the new Netgear switches also.
The point is redundancy if one switch fails, the LACP bound is still running on the remaining switch.
So 2x 1Gbit Ethernet are ok, but if you like to use both SATA Connectors for OSDs 4x 1Gb Ethernet would be better.
Because a high performance SATA HDD can have a data transferrate o up to 260MB/s.
So you have the brandwidth of 2 x 1Gb Ethernet per OSD or in a LACP 4x 1Gb Ethenert for two SATA SSDs.
This is full in the recommendation of CEPH for the OSD see the link above.
If you want to use big SATA SSDs to start small scale with big HDDS the ODROID-H2 is perfect because of the SO-DIMM slots you can put in up to 32GB RAM.
The biggest SATA HDDs on the market are now 16TB . And the recommendation of CEPH is 1GB RAM for 1 TB for HDD Space in the OSD .
You have 32GB RAM available so its is perfect for up to 2x16 TB HDD the biggest SATA HDDs currently available.
And if you use a hypervisor like Proxmox, which supports Ceph quite well you can use the spare RAM for VMs like pfSense, a PBX etc if you use a VLANs .
If you put your WAN , Storage, and PBX etc. in separate VLANa.
A perfect small and efficient solution which excellent scalability, especial for small to medium companies.
If you add a modular case like on the ODROID-HC2 may be for a 19" enclosure and power plugs for redundant 12V power of a standard PC & 19" power supply you can sell it as modular Microserver Modules.
Adjustable for the needs of the users.
Add a How to on the forum and it will sell by it self.
It is like a small mircroserver where you can experiment with CEPH but without the cost of a server cluster appliance like the "Ambedded Mars 400 (Ceph) microserver plattform".
The 32GB SO-DIMM give the opportunity to use it for low performance virtualization task as well as for CEPH.
Modules with access for hot swap able HDDa in a 19" enclosure would greatly improve the acceptance because, convincing your boss on something where he can see the CPU and the HDDs are screwed fix is not really convincing.
But it you can sell in in that way it could be a perfect solution or many people who want to have a professional solution but don't want to start with an investment of at least 5000$.
And when you reduce to cost for investigating with a somewhow professional option which is also good in performance you have a winner.
Only a OSD node with a SSD would need 10GB Ethernet in a Ceph environment by to way but 2x 1GB per SATA HDDs is ok.
By the way i try to use a m.2 2x 1GB ethernet controller on my ODROID-H2 which i have received today.
It is not a good solution but so i get the brandwidth.
If hope to see a killer product, which in this case may don't need a very high power CPU because of the small task. But it may sell better because you nearly can't get a SBC x86 CPU with 32GB RAM and more than 1x 1GB Ethernet.
Do it prepare a demo solution for CEPH and spread the possibilities.