Simple DIY USB based hard drive rack with "unlimited" expansion possibilities

This is a post about a simple DIY USB harddisk rack project I did a couple of years ago. Though a little outdated, the principles are still valid at the time I write this.

I have a small server at home use which ran out of SATA slots when I needed to install more hard drives to satisfy my MythTV recording storage need. MythTV was which was filling up all available space by the hour. There were a couple of available solutions to the problem:

1. install another I/O card,
2. buy a NAS,
3. setup a new server, or
4. buy external USB HD containers.

I wanted a solution which allowed for simple "unlimited" future expansion without too much hassle. None of the above solutions really fulfilled my requirements. The server case was already filled with hard drives so an added I/O card would not work. Setting up a new server seemed to bothersome and expensive since I already had a server, and having another server to maintain wasn't really something I was looking forward to. Buying external USB containers wasn't a good solution either since that meant that the snake pit of power outlets and cables would grow unmaintainable. An NAS was the most attractive alternative, but shelling out more than $500-600 for a 5 slot NAS wasn't economically attractive either. So I decided to come up with a different solution to the storage space problem by combining the server alternative with the USB container alternative. This solution allows for basically unlimited storage expansion with just using one or two power outlets and only one USB port on the server:

The principle is to have a single case which only contains a PSU, and install all hard drives on a USB HUB inside the case using USB-to-SATA adapters. Here is what I bought for my installation:

• $20 Computer case with PSU
• $5 Four port USB powered USB HUB
• $2 USB extension cable
• $20x2 USB to SATA adapter cable
• $67 Total

Below is the case I had lying around which I used until its PSU broke down and I bought the $20 replacement case. The case below is from the late stone age and had only two 3.5" slots, but it was quite sufficient to use for proof-of-concept.

Below is the USB to SATA converter I used in the project. Only the cables on the right were needed, the rest is just so much computer trash.

Here is a shot of the concept behind the system: the HD is connected to the converter which is connected to the USB HUB, which then is connected to the server via a USB extension cord (not shown).

And here is the complete system with two attached HDs. If you look closely you'll see that the HD mounted in the rack is an old IDE drive. The drives get their power from the PSU. Note: you will need to short circuit two of the connectors on the motherboard connector on newer PSUs to make the PSU start at all. Here is an article on it, and here is a video. You take responsibility of not frying your PSU in the process - make sure to verify that the PSU relly need short circuiting.

A new USB to SATA converter is needed for each new hard drive which is added to the system, and later on new USB HUBs are added to support more HDs. All the space where the motherboard normally is located is available for more HDs.

My experience is that this configuration was sufficient for use as a bulk storage system, and I had no issues with recording multiple TV programs while copying large files from the server over the network. I had three HDs in the storage at its peak, after which the IDE drive failed and one of the converters broke down. USB 2.0 is running on 480 Mbit frequency, which may possibly cause congestion if many of the drives are accessed in parallel (I lack deep knowledge of the USB transport inner workings).

Still, if you are looking for an idea for a bulk storage solution without adding servers or expensive NAS racks, perhaps this is something for you.