SOLVED Hardware Selection for Home NAS

[Vortigern]

Dear All,
I'd like to build my own NAS and use TrueNAS as OS. I've been reading through hardware documentation guide TrueNAS Community Hardware Guide 2021-01 Edition Revision 2a) and got the basic concepts of what's needed to properly build a NAS and I nailed it down to a couple of builds: I need your support to decide what's the better choice. Moreover I have some additional questions which apply to both builds.

Requirements​

First off a list of requirements for the NAS build. Please note "shall" is used as "must" while "should" as "desirable/goal". Here below the list:

• It shall fit into an IKEA piece of furniture: 335x335x390 (mm).
• It shall host at least four (4) 3.5" drives. This is in order to use regular magnetic hard drives.
• It should (goal) support ATX power supply.
• It shall allow simultaneous usage (both read/write) by three (3) or more clients.
• It shall support redundancy: as a minimum shall be configured as RAIDz1. RAIDz2 is a goal for this configuration.
• It should be as silent as possible without impacting the performances.
• It shall be fast, reactive and reliable.

Builds​

Here below the builds I have in mind. Please note that none of those reports the boot device nor the HDD to be used for the RAID configuration for the following reasons:

• As RAID drives I will be using WD Red Plus 4TB. The price will affect both builds equally.
• I have not decided yet on the boot drive: see below.

BUILD 1
CASE​	L (mm)​	H (mm)​	P (mm)​	PSU​	Motherboard​	3.5″ slot​	Price​
Fractal Design Node 304​	250​	210​	374​	ATX (up to 160 mm in length)​	Mini ITX, Mini DTX​	6​	118​
CPU​	Core/Thread​	TDP (W)​	ECC​	Socket​	RAM​	CPUbenchmark​	Price​
Intel Core i3-9100F​	4/4​	65​	Yes​	FCLGA1151​	DDR4-2400​	6772​	105​
RAM​	Capacity [GB]​	CL​	Frequency (MHz)​	ECC​	REG​	Quantity​	Price​
Mushkin MPL4R240HF16G14​	1x16​	17​	2400​	Yes​	No​	2 (32 GB)​	177​
MotherBoard​	Form Factor​	Chipset​	Socket​	RAM Slots​	SATA​	M.2​	Price​
Supermicro X11SCL-iF​	Mini-ITX​	Intel C242​	FCLGA1151​	2​	4xSATA3​	1 (FF 2280)​	275​
Power Supply​	Power (W)​	Fanless​	Form Factor​	Length (mm)​	​	​	Price​
Corsair RM550x​	550​	Semi​	ATX​	160​	​	​	76​
TOTAL​	​	​	​	​	​	​	€ 751​

BUILD 2
CASE​	L (mm)​	H (mm)​	P (mm)​	PSU​	Motherboard​	3.5″ slot​	Price​
Fractal Design Node 304​	250​	210​	374​	ATX (up to 160 mm in length)​	Mini ITX, Mini DTX​	6​	118​
CPU​	Core/Thread​	TDP (W)​	ECC​	Socket​	RAM​	CPUbenchmark​	Price​
Intel Xeon E-2334​	4/8​	65​	Yes​	FCLGA1200​	DDR4-3200​	13189​	328​
RAM​	Capacity [GB]​	CL​	Frequency (MHz)​	ECC​	REG​	Quantity​	Price​
Kingston KTD-PE432E/16G​	1x16​	22​	3200​	Yes​	No​	2 (32 GB)​	158​
MotherBoard​	Form Factor​	Chipset​	Socket​	RAM Slots​	SATA​	M.2​	Price​
Supermicro X12STL-IF​	Mini-ITX​	Intel C252​	FCLGA1200​	2​	6xSATA3​	1 (FF 2280)​	340​
Power Supply​	Power (W)​	Fanless​	Form Factor​	Length (mm)​	​	​	Price​
Corsair RM550x​	550​	Semi​	ATX​	160​	​	​	76​
TOTAL​	​	​	​	​	​	​	€ 1'020​

​

Considerations​

General​

I live in Switzerland so also availability of parts plays a role and price might be different with respect to EU or USA. The prices are anyway reported in euros.

Case​

I've opted for the Fractal Design Node 304 because it fits ATX power supply and I do not plan to have more than six (6) drives in RAID. Moreover this case provides a good solution for airflow with silent fans. Silverstone DS380 might be an alternative but it is cramped, only supports SFX power supply and is about € 50 more expensive.
Any suggestion for a different case that could host uATX in such a small space (335x335x390) would be highly appreciated!

CPU​

I opted only for CPUs that supports ECC. Cpubenchmark score is reported just as reference although it won't be fully representative of the actual performance difference in this use-case I can still use it to figure out what could be the difference when they're pushed to the limit. Intel Xeon E-2324G would be an option for "Build 2" and allow for €45 saving. Intel Xeon E-2314 is nearly impossible to find.

RAM​

Here I'm just picking the cheapest RAM with ECC I can find. Funny enough the 3200 MHz modules are cheaper than the 2400 MHz equivalent. About the RAM size I though 32 GB to be more than enough and maybe a single module of 16 GB could do as well. Don't know if it's worth to go to 64 GB though.

Mother Board​

It was a very difficult decision! Being bond to miniITX form factor the choice is limited and I had to do several tradeoffs: number of SATA ports, RAM slots, CPU socket. Since I would like to use RAIDz2 for double parity a 6 disks configuration would be much better but the Supermicro X11SCL-iF has only 4 SATA ports so I would end up using an expansion card. On the other side the Supermicro X12STL-IF supports 6 SATA ports but also requires more expensive CPUs. I've also considered motherboards with integrated Xeon-D but I wasn't fully convinced: very expensive and with lower performances although provigind more RAM slots.

PSU​

I've been reading detailed reviews about the Corsair RM550x (only Nippon Chemi-Con capacitors) and it has the highest performance/price ratio I could find. The Seasonic Prime PX-500 Fanless is also extremely good but it costs twice as much.

RAID Drives​

I would go for Western Digital RED plus 4 TB: they have a reasonable price and performances. The quantity would be initially 4 with possibility to go to 6 drives. I'm fully aware that 4 drives in RAIDz2 would equal to 50% of the capacity.

Boot Drive​

I though about using an NVMe drive as boot device. The current solutions could be:

• Kingston DC1000B 240 GB with Power Loss Protection (PLP) € 80
• Intel 670p 512 GB withOUT PLP € 51

Questions​

Here below the points for which I need your support:

1. Which build is the better one for the intended use (home usage, including plex, for a maximum of 3 clients simultaneously)? Of course the cheaper the better.
2. How much RAM (total and for each slot)?
3. Will I get any benefit from the Xeon CPUs at all? Is there any advantage of the Intel Xeon E-2334 CPUs with respect to Intel i3-9100 when it comes to RAIDz2 with compression plus encryption?
4. Can I expect any performance impact from LZ4 compression? From what I've been reading LZ4 is very inexpensive compression method and the CPU load should negligible on modern CPUs. Reference: ZFS Raidz Performance, Capacity and Integrity.
5. Is it really needed to have Power Loss Protection (PLP) on the boot drive?
6. Is a SLOG device recommended or would the ZIL be enough with only a marginal impact on performance in this use-case? Would I even notice the differences between the two solutions?
7. Is there any bottle neck that I couldn't spot in the given builds?

I would like to thank all of you in advance for your support!

Vortigern.

 

[Ericloewe]

Boot Drive​

I though about using an NVMe drive as boot device. The current solutions could be:

• Kingston DC1000B 240 GB with Power Loss Protection (PLP) € 80
• Intel 670p 512 GB withOUT PLP € 51

That's one area to save cash. Just get whatever's cheapest from Intel, Samsung, WD, etc. PLP will do you no good on the boot device, really. I guess you could repurpose it as an SLOG if you really needed to... But you don't, given your stated workload.

Is a SLOG device recommended or would the ZIL be enough with only a marginal impact on performance in this use-case? Would I even notice the differences between the two solutions?

See above.

Is it really needed to have Power Loss Protection (PLP) on the boot drive?

Not in the slightest!

Which build is the better one for the intended use (home usage, including plex, for a maximum of 3 clients simultaneously)? Of course the cheaper the better.

Even the i3 should be pretty beefy, but I'll let someone with Plex experience handle the details. If you don't actually want to transcode in real-time, it will absolutely be plentiful.

Will I get any benefit from the Xeon CPUs at all? Is there any advantage of the Intel Xeon E-2334 CPUs with respect to Intel i3-9100 when it comes to RAIDz2 with compression plus encryption?

Nothing Earth-shattering.

Is there any bottle neck that I couldn't spot in the given builds?

Not a bottleneck per se, but I'd avoid relying on a SAS controller to get to six disks. It's a lot of extra power (~10 W).

 

[Vortigern]

Dear Ericloewe,
thank you very much for your reply! I would like to summarise it as follow:

• CLOSED > Boot Drive: just the cheapest one and dimension is not relevant as well.
  • I will probably go for HP EX900 120 GB, no PLP, which is € 31
• CLOSED > SLOG: no need for SLOG device
• OPEN > CPU: even i3-9100 should be enough for data access. About Plex usage I've just found this article which recommends 2000 PassMark score (same as the ones I've reported in the first post) for full transcode at 1080p and 6 times more (12000) for 4k SDR. Based on this very synthetic information the i3-9100 would be more than enough for 1080p while the Xeon E-2334 is just enough for 4k SDR.
• CLOSED > Bottle neck: not identified.

Have you got any suggestion for the other open point?

• OPEN > Case: is there any better option than the one I've selected?
• OPEN > RAM quantity/type considering that I'd like my system to be future proof.
  • Is it better to start with 2x16 GB or 1X32GB? The former should have an advantage in terms of speed while the latter is better for the future giving the option to expand it to 64 GB? But I don't know if 64 GB will be ever needed for this use case (at least in the next 10/15 years, when probably a complete rebuild would make sense)
• OPEN > Mother Board: is there any better solution to have 6 SATA ports, 1 NVMe, miniITX form factor, ECC support and FCLGA1151 socket (option to use the cheap i3)?
  • AsRock Rack C236 WSI would do great but I cannot find it on online shops!

Cheers

 

[Davvo]

Your case and motherboard selections are good, you won't probably find something significantly better for those prices. ITX means you have to compromise on some things.

About RAM, in TrueNAS it's always better more than fast.

 

[Etorix]

On the other side the Supermicro X12STL-IF supports 6 SATA ports but also requires more expensive CPUs. I've also considered motherboards with integrated Xeon-D but I wasn't fully convinced: very expensive and with lower performances although provigind more RAM slots.

Good analysis, and in my opinion good pick of case. (i just hate working with the DS-380, and it's impossible to cool quietly with HDD in there!)
Do get a motherboard with at least 6 SATA ports to make the best of it.

If transcoding is intended, go for an i3/Xeon with an iGPU.
Else the Xeon D-1500 would have been a good match for the case, possibly with on-board (copper) 10 GbE, and in any case with slots for RDIMM (second-hand RDIMM is cheap and plentiful). There are two boards for offer on eBay.de around 400E right now, which is not cheap but less than what you're planning to spend on MB+CPU.

Beware: Transcoding is NOT supported with C242, this requires C246. I don't know how transcoding works with the C250 series.

 

[Vortigern]

Dear Davvo and Etorix,
thanks for your answers. Thanks a lot for reporting issues with the DS-380 operations: quietness is one of the requirement.
Hardaware Transcoding > Based on your comment I will give up on hardware transcoding: it is not supported on C2X2, at least a C2x6 with iGPU is required. I couldn't find anything from Supermicro with C246 in miniITX form factor, ASRock C246 WSI would do but it's expensive and I will need an additional expensive OCuLink to SATA cable. Moreover, according to another forum the iGPU might even be unpowered on server motherboards. I don't want to make it too complex so I will rely on software transcoding.
Xeon D > I've evaluated this option and I can get the Supermicro X10SDV-4C-TLN2F (Intel Xeon D-1521) at about € 700 new, but:

• I'm not a fan of the integrated CPU I don't know how the CPU cooling would be in a non-rack case.
• CPU score is about 5876 on PassMark (lower than the i3-9100)
• The price is higher than the "Build 2" CPU+Motherboard and I cannot get easily stuff from ebay.de

Any other suggestion or things I should consider?

Cheers

 

[Davvo]

Just be aware that you need an HBA to add more drives after you full your mobo SATA ports.

 

[Etorix]

To cool the puny Xeon D-1500, just slap a Noctua NF-A6x25 on the heatsink and forget it.

The comment on STH is unqualified. As noted by the next poster, at the very least the C246 WSI is guaranteed to have working iGPU since it is a workstation board and has display ouputs. Though for NAS use I'd prefer the E3C426D2I (apparently same PCB, but with a BMC for server use). Both boards are reportedly (Geizahls) available in Germany for 15-25E more than the X11SCl-IF, but I don't know how that works out in Switzerland. A special cable is better than a HBA in the sole PCI slot.

 

[Vortigern]

Dear both,
thanks again for your quick and valuable answers: much appreciated!

Motherboard > I was reading as well First TrueNAS build - plerase sanity check part list and there's a long discussion on why using server grade components rather than workstation components. ASRock Rack E3C246D2I would be the server edition of the ASRock C246 WSI and has got the BMC, which I really like, but has no HDMI port and a dedicated graphic controller ASPEED AST2500. I couldn't find much in the user manual about the iGPU usage for the ASRock Rack E3C246D2I. Moreover the E3C246D2I supports only NVMe with 2242 form factor which are more expensive than the 2280.
By the way is there any speed limitation when using OCuLink? Is there any limitation from controller point of view on the E3C246D2I? Of course having a 1 Gb/s NIC would kill all the considerations on the OCuLink speed but if I select the Supermicro X12STL-IF I would still have 6 SATA3 ports and the option to add a 2x10 Gb/s NIC on the free PICe slot.

NIC > I would actually like to know if it would be better to have 10 Gb/s ports (e.g. Supermicro X10SDV-4C-TLN2F) or if 2x1 Gb/s are already enough (no plan for anything different than RJ45 here). I still need to learn a lot and would like a good guide to better understand how to configure the NICs: I'll start a separate thread for the software configuration. Nonetheless if you already have a good guide would be very useful.

CPU > very nice tip about the Noctua fan! Is it working with U.L.N.A?

Cheers

 

[ChrisRJ]

What is your use-case? You mention 3 concurrent clients, but that doesn't mean anything. Are we talking about people working on office documents (as an example for low-end scenario), or is it 8K video editing directly on the NAS by 3 folks (high-end example).

If possible, describe things in terms of what you want to achieve, rather than how to do this.

 

[poldi]

Gee I tell you you are going to hate the 1Gb/s networking very soon.
Even with only 4 spindles the array will be able to saturate the 1Gb/s link handily.
2,5Gb/s+ networking is quickly becoming the standard on modern PCs or laptops. You can even run 10Gb/s over cat5e for short distances (should not be an issue in most houses or apartments in Europe).
Normally I would say you can get a cheap 10Gb/s PCIe card on eBay but since you only have 1 PICe slot I would try to get as much on board as possible (if affordable).

 

[ChrisRJ]

Gee I tell you you are going to hate the 1Gb/s networking very soon.

Without knowing the use-case that is not a particularly helpful statement.

Even with only 4 spindles the array will be able to saturate the 1Gb/s link handily.

That depends entirely on the workload (random vs. sequential access, sync vs. async), the vdev setup, how much space is left in the pool, etc. So as an absolute statement it is simply wrong.

 

[Etorix]

I couldn't find much in the user manual about the iGPU usage for the ASRock Rack E3C246D2I.

In doubt, you may ask AsRockRack directly…

Moreover the E3C246D2I supports only NVMe with 2242 form factor which are more expensive than the 2280.

Well spotted! But you only need the smallest and cheapest NVMe drive you may find in 2242 (SATA would take a lane from the motherboard ports, NVMe is "free"). Second-hand/small ads are a good source of such cheap exotic devices.

By the way is there any speed limitation when using OCuLink?

OCuLink, MiniSAS or MiniSAS HD are just connectors which package four lanes of I/O (SATA and/or PCIe) in a small space. There's no speed difference compared with four 7-pin SATA ports.

Of course having a 1 Gb/s NIC would kill all the considerations on the OCuLink speed but if I select the Supermicro X12STL-IF I would still have 6 SATA3 ports and the option to add a 2x10 Gb/s NIC on the free PICe slot.

I'm unsure what the suspected conflict between OCuLink and networking might be… These are independent.
As long as the PCIe slot remains free, you may add a 10 GbE NIC later.

CPU > very nice tip about the Noctua fan! Is it working with U.L.N.A?

Certainly, but the 60mm fan at full speed can not be heard from 30 cm away, much less when the case is closed.

 

[poldi]

Without knowing the use-case that is not a particularly helpful statement.

That depends entirely on the workload (random vs. sequential access, sync vs. async), the vdev setup, how much space is left in the pool, etc. So as an absolute statement it is simply wrong.

I don’t think you read the post. I think high IOPS VM storage, sync writes etc. is definitely out of scope here.

He said it all above. He wants to have a Plex server on there and then he mentions 3 connected clients.

So what does that tell me? He is going to have lots of movies on there.
Ever copied a 4k UHD rip to the NAS over a 1Gb/s interface … well let me tell you a secret, it is going to take a very long time and the main thing holding you back is going to be the interface.
Secondly 2,5Gb/s is becoming the standard. Hell even Wifi is on the cusp of being able to run faster than 1Gb/s.
So all I am saying is, if you can get the 10Gb/s interface on board and you can afford it, then try to get it. He might not need it now, but multi-gig networking in the home is going to be ubiquitous very soon.
Of course you can say that used 10G PCIe cards are cheap (<€100) to get on eBay if you need one. That is true but he is planning to get an ITX board, so one 1 PCIe slot is all he has (no issues here with the choice of ITX btw, they make nice small form factor builds).
And then I repeat, investing in a good onboard NIC is going to be worth its weight in gold.

 

[Vortigern]

Dear ChrisRJ, poldi and Etorix,
I really appreciate your support. I'll try to comment on your answer/questions below.

NVMe > It is clear that I can get a used M.2 2242 but I can get new HP EX900 M.2 2280 120 GB or Crucial P2 M.2 2280 250 GB (5 y warranty) for ~€ 30. The price for a NVMe M.2 2242 is going to be nearly twice as much (VAT + customs taxes) as the M.2 2280.

OCuLink clarification > thanks for the clarification, although my understanding of OCuLink is different. OCuLink should be a cabled PCIe and has a different bandwidth depending on its revision. Nonetheless by reading What is OCuLink? (2017) even the initial release of OCuLink supports 32 Gbps. My comment on the possible conflict with the network is the following: if the pool speed is higher than the network link anyway the bottleneck will be the network and not the HDD communication. E.g. a single SATA 3.0 port has a maximum theoretical throughput of 6 Gb/s meaning it should not saturate a 10 Gb/s ethernet communication (even with the overhead) but it can easily saturate a 1 Gb/s link.

Use-case > I'm sorry if I was not clear enough in my first post. Poldi got it right: I'm going to use the NAS to store movies which I would like to stream on my TV via Plex. Plus I also consider using the NAS to store and edit photos (nothing too fancy) and to save/access documents (basically a replacement to my data drives). I haven't got an awful amount of data: it's just about 2 TB. That's why I'm planning on using 4 drives of 4 TB in RAIDz2: 8 TB of nominal pool storage with only 25 % usage (presumed to increase but I wouldn't go above 75 % in any case: I'd rather start buying additional drives).

NIC > That's the most important factor at the moment about the decision for the motherboard. My motherboard options are:

• Supermicro X11SCL-iF: dual 1 GbE, 4 SATA3 ports
• Supermicro X12STL-IF: dual 1 GbE, 6 SATA3 ports
• Supermicro X10SDV-4C-TLN2F: Xeon D-1520, dual 10 GbE, 6 SATA3 ports

My plan is to start with a pool of 4 HDDs with option to increase it to 6. This means: I would need a HBA SAS controller on the X11SCL-iF to attach 2 additional HDDs (no chance to install a NIC to get 10 Gb/s port). On the X12STL-IF I wouldn't need a HBA SAS controller (6 SATA3 ports) but I might be needing the 10 GbE card. On the other hand the X10SDV-4C-TLN2F has both 6 SATA ports and 10 GbE but the processor (Xeon D-1520, PassMark 3324) is not on par with the CPU I can install on the other motherboards for the same price (e.g. Core i3-9100 PassMark 6635, Xeon E-2334 PassMark 13189). As mentioned before I need to stick to the given dimensions and I couldn't find any case supporting uATX motherboard in such a small space. So the question here is: shall I go for a slow CPU (Xeon D-1520) + 10 GbE and leave a free PCIe slot or take a motherboard with a faster CPU but use the available PICe slot for a 10 GbE card?

Cheers

 

[Davvo]

I would get as much as possibile on the board. In the future you might want that PCIE slot for a VGA in order to use hardware encoding.
As a side note, expanding anything but striped mirrors is not so nice.

 

[poldi]

• Supermicro X11SCL-iF: dual 1 GbE, 4 SATA3 ports
• Supermicro X12STL-IF: dual 1 GbE, 6 SATA3 ports
• Supermicro X10SDV-4C-TLN2F: Xeon D-1520, dual 10 GbE, 6 SATA3 ports

If these are the options then let me think.
I think by your own account the X11SCL-iF is out, simply due to the amount of SATA ports you are boxed in from the start.
I always looked for my possible upgrade path in the future.
In that sense the X10SDV-4C-TLN2F could be a fair option if you can score it used but I share you skepticism regarding soldered CPUs.
And hence the X12STL-IF would be the winner. You have the option to upgrade the CPU down the line. It has enough SATA ports and you still have the PCIe slot for networking, graphics etc.
Btw. for small NAS builds I always found Brians Blog (here) to be inspiring. He builds a new NAS mostly based on ITX every year and lists the parts. This year he is going with the X11SDV-4C-TLN2F (specs). Passmark lands at around 8000 for that CPU (I know it is soldered sorry) and otherwise the specs are very neat. Only downside giezhals lists it for around €800

 

[Etorix]

@Vortigern As described you will be spending a lot of money for a relatively small amount of storage, especially if buying new. And mini-ITX brings many constraints for future expansion (HBA, network, GPU for hardware transcoding).

Pool design is also a constraint. With 4 TB drives, a stripe of mirrors is possible, and could be extended to six drives with a third mirror and/or by replacing just the two drives of a mirror pair by larger ones; but this geometry will become less safe with larger drives. Raidz2 is quite safe, even with larger drives, but cannot be easily extended so it would be desirable to begin with all six drives; if you begin with four, the only way to add drives is "backup-destroy-restore". Increasing size with raidz2 requires replacing all drives.

No HDD can saturate a 3 Gb link, much less a 6 Gb link.

The way I see it:

Supermicro X11SCL-iF
- 4 SATA3 ports
- no iGPU transcoding
- one single PCIe slot for hardware transcoding, NIC or HBA
In this generation, a C246 board (AsRockRack), with 6 SATA ports and iGPU transcoding, would be a much better overall option, its only drawback being the uncommon 2242 boot drive.

Supermicro X12STL-IF
+ 6 SATA3 ports
? transcoding
- price!

Supermicro X10SDV-4C-TLN2F
+ dual 10 GbE
+ 6 SATA3 ports
+ 4 RDIMM slots for lots of relatively cheap memory (but that may not be a priority)
- worst SMB performance
- requires dGPU for hardware transcoding (but everything else is already on-board)

Two last tips about X10SDV boards:
For quietness, get one without a fan and put a 60mm Noctua on the heatsink. Boards with a fan (-nC+ models) have a high pitch noise and the little screamer is screwed from the bottom so one has to take off the heatsink to remove the fan, which is a slightly risky operation on an expensive board.
"Revision 2" boards can bifurcate their PCIe slot in all possible ways and have a better fan control model, with two zones. Fan control scripts are available on this forum.

 

[Etorix]

And hence the X12STL-IF would be the winner.

Funny: That would be my instant loser, on the price criteria.

Btw. for small NAS builds I always found Brians Blog (here) to be inspiring. He builds a new NAS mostly based on ITX every year and lists the parts. This year he is going with the X11SDV-4C-TLN2F (specs). Passmark lands at around 8000 for that CPU (I know it is soldered sorry) and otherwise the specs are very neat. Only downside giezhals lists it for around €800

Xeon D-2100 is overkill for the use case, and may still require a GPU for 4K transcoding, but 800 E looks like a excellent price for a X11SDV—except for "Lieferung nur innerhalb Deutschlands" in Geizahls!

The decision is highly personal, and will largely rest on what's available to @Vortigern in the "little island" market of Switzerland, including second-hand (or willingness to go for it).

 

[poldi]

Funny: That would be my instant loser, on the price criteria.


Xeon D-2100 is overkill for the use case, and may still require a GPU for 4K transcoding, but 800 E looks like a excellent price for a X11SDV—except for "Lieferung nur innerhalb Deutschlands" in Geizahls!

The decision is highly personal, and will largely rest on what's available to @Vortigern in the "little island" market of Switzerland, including second-hand (or willingness to go for it).

Well agreed it is a rock and a hard place.
I mean let's spell it out if you are looking for a server/workstation board that gets you IPMI, ECC support then this is a niche market. You are going to have issues sourcing the board and the price is going to be €400 and up.
Then throw ITX on top and you are left with only a handful of options.
@Vortigern don't let the above get to your head. ITX is still a very good starting point. I personally started out with an ASRock Rack E3C ITX variant with an E3-1240v2 and 4 disks as my first build. That was brilliant and it served me well for almost 4 years.

On the transcoding side my personal opinion is that hardware supported transcoding in Plex is actually overrated. Get a CPU that can technically handle one transcode and then call it a day.
Realistically most of your source material is going to be in h264. Most of your end devices, TVs, FireTV, Chromecast etc. accept h264 (even in 4k) natively these days. So there is no need to transcode.
That said in a family setting you will see the occasional transcode on you Plex server but you will not have parallel transcoding needs.
Unless of course you share your Plex server with all your friends and they all cancel their Netflix subscription.