ssd

For Pi Day, I'm going to livestream my second attempt at getting 16 hard drives (well, 12 hard drives and 4 SSDs) recognized by a Raspberry Pi.

The first attempt went decently well... but I wound up running into power supply issues.

This time around, I will hopefully have those issues solved, and also we may have a little fun building a software-RAID-on-hardware-RAID (depending on how crazy we want to get). It probably won't work like I expect, but that's what makes it fun!.

Ever since the Pi 2 model B went to a 4-core processor, disk IO has often been the primary bottleneck for my Pi projects.

You can use microSD cards, which aren't horrible, but... well, nevermind, they're pretty bad as a primary disk. Or you can plug in a USB 3.0 SSD and get decent speed, but you end up with a cabling mess and lose bandwidth and latency to a USB-to-SATA or USB-to-NVMe adapter.

The Pi 4 actually has an x1 PCI Express gen 2.0 lane, but the USB 3.0 controller chip populates that bus on the model B. The Compute Module 4, however doesn't presume anything—it exposes the PCIe lane directly to any card it plugs into.

And in the case of Oratek's TOFU, it's exposed through an M.2 slot, making this board the first one I've used that can accept native NVMe storage, directly under the Pi:

A few months ago, I posted a video titled Enterprise SAS RAID on the Raspberry Pi... but I never actually showed a SAS drive in it. And soon after, I posted another video, The Fastest SATA RAID on a Raspberry Pi.

Well now I have actual enterprise SAS drives running on a hardware RAID controller on a Raspberry Pi, and it's faster than the 'fastest' SATA RAID array I set up in that other video.

A Broadcom engineer named Josh watched my earlier videos and realized the ancient LSI card I was testing would not likely work with the ARM processor in the Pi, so he was able to send two pieces of kit my way:

I'm a fan of Raspberry Pi cases that keep my Pi cool. And the cases made by Argon Forty have great cooling, which is one reason they're a popular choice. Their latest Argon One M.2 case also adds a built-in high speed SSD drive slot!

A few months ago, someone from Argon Forty reached out and asked if I'd like to review the Argon ONE M.2, after they watched my video on booting a Pi 4 from an external SSD, and I accepted.

Unlike most Pi cases, this one actually adds features through it's design, like putting all the ports on the back, and adding a mostly-internal SSD, and so I decided to put it through its paces and see what I liked, and what I didn't like.

Video Review

I also posted a video version of this blog post on YouTube:

Since the day I received a pre-production Raspberry Pi Compute Module 4 and IO Board, I've been testing a variety of PCI Express cards with the Pi, and documenting everything I've learned.

The first card I tested after completing my initial review was the IO Crest 4-port SATA card pictured with my homegrown Pi NAS setup below:

But it's been a long time testing, as I wanted to get a feel for how the Raspberry Pi handled a variety of storage situations, including single hard drives and SSD and RAID arrays built with mdadm.

I also wanted to measure thermal performance and energy efficiency, since the end goal is to build a compact Raspberry-Pi based NAS that is competitive with any other budget NAS on the market.

In the past few weeks, I reviewed USB drive performance on the Raspberry Pi 4, and the importance of UASP support for USB drive performance.

Both posts generated great discussion, and there were three things I wanted to cover in this follow-up, namely:

1. Which drives support UASP
2. Real-world performance benchmarks
3. TRIM support

For reference, here are all the products I'm testing in this post (product links are to their Amazon product page, starting from top middle, clockwise):

I've been doing a lot of benchmarking and testing with the Raspberry Pi 4 and SSDs connected via USB. I explored UASP Support, which USB SSDs are the fastest, and I'm now booting my Pis from USB SSDs.

Anyways, one thing that I have wondered about—and some people have asked me about—is TRIM support.

I'm working on a new video for my YouTube channel that will go into some more detail on which of the drives I tested support TRIM, but while I was researching for that video, I also found that TRIM support in Linux is not as simple as it seems at first glance—it's definitely not plug-and-play, in my experience.

While internal microSD cards seem to support TRIM out of the box, none of the external USB drives I tested supported it out of the box. They all needed a little help!

For years, I've been maintaining benchmarks for microSD cards on the Raspberry Pi, but I only spent a little time testing external USB storage, due to historic limitations with the Pi's USB 2.0 bus.

But the Pi 4 cleared away the limitations with a full-speed USB 3.0 bus offering much better performance, so I've done a lot of testing with USB boot, and with all the USB SSDs I had at my disposal. You can see some of those results in this blog post and video on booting a Pi 4 via USB.

After posting my tests concerning UASP support in USB SATA adapters, I got an email from Rob Logan mentioning the performance of some other types of drives he had with him. And he even offered to ship a few drives to me for comparisons!

There's also a video that accompanies this blog post, for the more visually-inclined:

There is a companion video to this post: Is fast NVMe storage coming to the Raspberry Pi?.

A couple days ago, Tom's Hardware posted an article stating NVMe support might be coming to the Raspberry Pi Compute Module 4.

On the first episode of The Pi Cast, Eben Upton, the CEO of Raspberry Pi, said "microSD will always be the baseline for storage", but "it's fairly likely we'll support NVMe soon on the Compute Module 4, to some degree, using single-lane PCI Express." (Skip to about 11 minutes into the video for the NVMe discussion).

He also said NVMe support is not without cost, since there's an extra connector silicon required. And with the System on a Chip used in the Pi 4, there's also a tradeoff involved: There's only one PCIe 1x lane, and it's currently used for the Pi 4's USB 3.0. If you want to add NVMe support, you'd have to drop the USB 3.0 ports.

You can view a video related to this blog post here: Does UASP make the Raspberry Pi faster?.

A couple weeks ago, I did some testing with my Raspberry Pi 4 and external USB SSD drives. I found a USB 3.0 SSD was ten times faster than the fastest microSD card I tested.

In the comments on the video associated with that post, Brad Manske mentioned something I never even thought about. He noticed that I had linked to an Inateck USB 3.0 SATA case that didn't have UASP.

What's UASP, you might ask?