Possible to connect DIY DAS to a PC?

[danhendo888]

If not possible, I can ignore the below.
If possible, then I would like to understand what parts would be needed. Would like to be able to power off/on the DAS only when I need it.

DAS (using PC case + case fans)
4 x 12TB NAS HDD
Motherboard or Supermicro board?
Do I need a SAS expander on the motherboard? If yes, why?
How do I connect the HDDs?
Power Supply
No CPU, no RAM?


Cable:
Cable from the expander on the DAS to the LSI card on the PC?

PC:
Windows 10
Ryzen 3 3100
TUF GAMING B550M

http://imgur.com/hzz0Emr

2 x 8GB Vulcan Z 3200MHz DDR4
Kingston 500GB A2000 M.2 2280 NVMe
GTX 1660
CORSAIR RM850
be quiet! Shadow Wings 2 140mm (x3)

Do I need an LSI card on the PC's motherboard to connect the DAS to the PC? (I only have a PCIEx1 and a PCIEx16 slot available)

Trying to build a DIY DAS that works like a portable HDD. Something I can connect/disconnect whenever I want. No RAID or software required.

My options:
- insert SATA HDDs into my PC
- buy docking station
- buy DAS enclosure like Sabrent, Orico
- DIY

 

[oneplane]

It possible, but also kinda pointless.

As for the option:

1. You would not be 'building a DAS', but more like disk shelf
2. Internally that would mean the disks, some sort of disk backplane or just a bunch of cables
3. Those cables either go into a SATA or SAS expander
4. The SATA or SAS port for upstream goes to your PC
5. Your PC would need a port to connect to

Normally I'd be asking the following things and scenario:

Self-built directly attached storage (DAS) is not much more than an external disk, except that it's multiple disks in your case. If you also want to have the external storage box do extra stuff (like RAID or ZFS) you are not really building a DAS anymore, but rather something like a 1-node SAN.

It also really all depends on what your real goal is here. Do you just want a 'big external drive'? Because there would be far cheaper ways to do that. Or do you want "lots of storage, but not over the network"? Because there are options for that too. Or is it perhaps "I am using windows, but I know that ReFS and Spaces are bad so I want to use ZFS but Windows doesn't know how to do that so I want to put ZFS in a second box and present it as a single disk to Windows"?

But since you already wrote "I want to have it work like a portable HDD", wouldn't it be much easier for you to just buy an external JBOD tower? You could just connect that over USB and be done.

As for the parts: you'd need something like this: SAS Expander (I think there is a big topic around here with other cards like the ones from HP), it does some things that are kinda important like SES and fan control. You also need a way to turn on the power supply since without a mainboard ATX power supplies just stay off. On the PC side, you need a SAS card with an external connector, and then between your PC and the SAS expander you need a SAS cable to match both ports.

What might be much, much easier for you would be to get a USB-C card with Thunderbolt (or one of the older/cheaper Thunderbolt 2 cards), and a used Promise Pegasus. It has everything built in together, you can use them as JBOD boxes but also use their (IMO nasty, but better than Windows SoftRAID/ReFS/Spaces) RAID system. It's just a single cable, and once you eject the disk you can unplug the cable and the device goes into standby.

If you want more than 8 disks, you wouldn't be fitting those into a tower anyway, and at that point you might want to check out used disk shelves instead. Those are much bigger (because if you fit more disks in it... well it needs more space ) and generally are all wired up for SAS controllers anyway.

As for why you want to treat it as a big external disk, that might be an important thing to think about:

- Are you not enjoying network based storage?
- Do you want the same experience as a classic USB disk?
- Are your storage needs very small (i.e. less than 20TB)?
- Is your data not very important?

If so, you might as well just get something like a WD My Book Duo 28TB. Or just buy a 22TB SATA disk, slap a SATA-to-USB controller on it and off you go.

If your data is important, you probably have backups, and you probably also want to do something about data integrity. Restoring backups is slow (especially tens of TBs), and data you can't trust isn't super useful. That brings you back to ZFS and at that point you need a SAN or a NAS, not a DAS.