A How-To Guide: Building a Rudimentary Disk Enclosure

[Windows7ge]

What is a Disk Enclosure?

A Disk Enclosure is a case (most commonly rack mountable) that contains nothing but bare drives, a means to power the drives, and a controller for the drives to use to communicate with a parent system.

 

Why Would Somebody Want to Build One?

• Less expensive than off the shelf units (often cheaper than the used market)
• Quieter (being able to choose your own fans)
• Fully customizable (standard form factor)
• Easier to repair (standard form factor)

The Build Process (an example using Mini-SAS)

Starting with the enclosure virtually any box or container could be used to build a Disk Enclosure but a chassis designed to hold a lot of drives, a chassis with many 5.25" drive bays (for 2.5"/3.5" drive caddies), or a rack-mount chassis would be ideal.

 

The Power Source

Depending on the enclosure different form factors of PSUs are available including ATX, SFX, FlexATX, and server variations (1U, 2U, 4U)/Mini-Redundant/etc are all options. It's important to understand that larger quantities of disks are going to require a larger PSU. Not for the reason of standard operation power draw but because of initial spin-up power draw. Staggered Spin-up is a feature designed to mitigate this issue but your controller and/or SAS Expander may not support it. Depending on your choice of disks datasheets can be found online to tell you how much current (Amps) are required to get the drive spinning. By multiplying this by the number of disks you have (make sure to pay attention to both the +5V & +12V rails) it will give you an idea as to how strong of a PSU you'll need. Make sure to give yourself some overhead for future expansion.

 

The SAS Expander (the controller)

There are a variety of SAS Expanders on the market but this guide will only go over one. If you have reason to use another be it better quality, cheaper, or you already have it you may be able to adapt it to work with this guide.

 

One that will provide modularity and give you 24 ports for HDDs is the HP 468405-002.

 

 

It can be found on sites like Amazon & eBay for cheap. It comes with a SFF-8088 port (which will connect to your parent server) and eight SFF-8087 ports (6 of which will go to your drives/caddies/or backplanes, two of which can go to your HBA/Controller but we won't be using them).

 

Powering the SAS Expander can be done in one of two ways, which you choose may be determined by what you have available to you or how you've setup your box. The x8 slot on the SAS Expander isn't needed when the rear SFF-8088 port goes to your Controller. Because of this you can setup a low-end spare motherboard with CPU and RAM. This will just give it power. Then you could connect the front I/O cables to the motherboard for controlling power/reset.

 

An alternative option would be to use one of the powered PCI_e risers made for GPU Crypto Mining.

 

 

Some people have reported this hasn't worked for them but instances of this haven't been checked that it wasn't user error. Never-the-less, this method may or may not work for you but it would be a lot cleaner and when building your own box, easier than mounting a full motherboard. Powering the Disk Enclosure on/off could be handled by shorting pins 15+16 (Green wire to a Black wire) on the 20+4 pin cable from the PSU then operating power by using the switch on the back of the PSU.

 

Additional Components

 

 

• SFF-8088 to SFF-8088 cable
  • This cable will run externally to the Disk Enclosure and will connect to your server.
• HBA/RAID Controller (with external ports)
  • An HBA or RAID controller with external ports (such as the LSI 9207-8e) will be needed in your server for the Disk Enclosure to interface with it.

 

Optional Components

 

 

• SFF-8087 Cable
  • This will be needed for connecting the SAS Expander to your backplane if you're using one.
• SFF-8088 to SFF-8087 adapter
  • In the event you have an HBA/RAID controller with internal ports this paired with SFF-8087 cables will allow you to use it in substitution of a controller with SFF-8088 ports.
• SFF-8087 to SATA Forward Breakout cable
  • If you are connecting the SAS expander to drive caddies or directly to the drives these will be needed.

 

Assembly

Connecting everything together is quite strait forward.

1. Install the HBA/RAID controller in your server.
2. Connect SFF-8088 cable to the back (or though SFF-8087 to SFF-8088 adapter)
3. Assemble the Disk Enclosure
   1. Install your drives
   2. Connect SFF-8087 cables to backplane or breakout cables directly to the drives/caddy)
   3. Install PSU
   4. Install unpopulated motherboard or powered PCI_e riser
   5. Install SAS Expander, connect SFF-8087 cables.
   6. Connect other end of SFF-8088 cable to Drive Enclosure
   7. Connect power

 

Testing

Once assembled a Disk Enclosure is very plug'n'play. Be sure to power up the Disk Enclosure before the server. Your HBA or RAID controller will see the disks connected though the SAS Exapnder and will appear within the OS for whatever you need them to do.

 

Conclusion

Building a Disk Enclosure yourself is a very cheap fully customizable option to expanding storage on your desktop or server. How far you want to go with it is entirely up to you.

[bigo93]

Thanks

 

Can I use a motherboard without a CPU in it or RAM in a spare PC case as my disk enclosure?

[Windows7ge]

24 minutes ago, bigo93 said:

Thanks

 

Can I use a motherboard without a CPU in it or RAM in a spare PC case as my disk enclosure?

So long as the board powers on yes you can.

[bigo93]

12 minutes ago, Windows7ge said:

So long as the board powers on yes you can.

Nice! I accidentally somehow bent pins on an old MB CPU socket, nothing else wrong with it

Just ordered this one, looks similar to yours, HP 24 Bay SAS Expander Card 487738-001 468405-001

So I guess that P222 card was the right thing I ordered and so already have that piece.
So a project for me to do next weekend!
Thanks again, ill let you know how it turns out.

[Windows7ge]

4 minutes ago, bigo93 said:

Nice! I accidentally somehow bent pins on an old MB CPU socket, nothing else wrong with it

Just ordered this one, looks similar to yours, HP 24 Bay SAS Expander Card 487738-001 468405-001

So I guess that P222 card was the right thing I ordered and so already have that piece.
So a project for me to do next weekend!
Thanks again, ill let you know how it turns out.

I'd have to read up on the data sheets to know what the difference is between the 001 & 002 models but both are 3Gbit. This is a solution for slower denser storage.

 

Looking up the P222 I see you're going the hardware RAID route. If that's what's compatible with your microServer. I don't know what RAID implementations the software offers.

[bigo93]

@Windows7ge

Need to add the following, apparently most motherboards will not fully power the expander if they dont have a CPU installed

 

Easy way to tell if the SAS Expander will work in your motherboard is:
Turn it on.
If LED R6 is remains Solid Green permanently then your motherboards isnt powering it up fully
If LED R6 is Solid Green for a few seconds, then goes to a continuous blink, then it's powered up properly

 

If you get a constant Solid Green LED then you will need to use a PCI-e Riser instead.

 

LEDs R4 and R5 always seem to be off, idk why

But you need R6, the top one in this photo to be blinking, otherwise the expander will not work.

 

 

[Windows7ge]

1 hour ago, bigo93 said:

Need to add the following, apparently most motherboards will not fully power the expander if they dont have a CPU installed

 

Easy way to tell if the SAS Expander will work in your motherboard is:
Turn it on.
If LED R6 is remains Solid Green permanently then your motherboards isnt powering it up fully
If LED R6 is Solid Green for a few seconds, then goes to a continuous blink, then it's powered up properly

 

If you get a constant Solid Green LED then you will need to use a PCI-e Riser instead.

 

LEDs R4 and R5 always seem to be off, idk why

But you need R6, the top one in this photo to be blinking, otherwise the expander will not work.

 

When I find the time I will edit the guide to include this.