Wow: NVMe and PCIe Gen 4

Recently it’d come to my attention that my old PC rig wasn’t cutting it.

Considering it was 10 years old, it was doing really well. I mean, I went from HDD to 500 GB SSD to 1 TB SSD, up’d the RAM, and replaced the GPU at least once. But still, it was a 4-core system (8 threads) and it had performed admirably.

The Intel NIC was needed because the built-in ASUS Realtek NIC was a piece of crap, only able to push about 90 MB/s. The Intel NIC was able to push 120 MB/s (close to the theoretical max for 1 Gigabit which is 125 MB/s).

The thing that broke the camel’s back, however, was video. Specifically 4K video. I’ve been doing video edits and so forth in 1080p, but moving to 4K and the power of Premerier Pro (as opposed to iMovie) was just killing my system. 1080p was a challenge, and 4K made it keel over.

I tend to get obsessive about new tech purchases. My first flat screen TV purchase in 2006 was the result of about a month of in-depth research. I pour over specs and reviews for everything from parachutes (btw, did you know I’m a skydiver?) to RAM.

Eventually, here’s the system I settled on:

AMD came out of nowhere and launched Ryzen 3, which put ADM from a budget-has-been to a major contender in the desktop world. Plus, they were the first to come out with PCIe Gen 4.0, which allowed for each lane of PCIe to give you 2 GB/s of bandwidth. m.2 drives can connect to 4 lanes, giving a possible throughput of 8 GB/s of bandwidth.
Compare that with SATA 3, at 600 MB/s, and that’s quite a difference. SATA is fine for spinning rust, but it’s clear NVMe is the only way to unlock SSD storage’s potential.
When I built the system, I initially installed Linux (CentOS 7.6, to be exact) just to run a few benchmarks. I was primarily interested in the NVMe drive and the throughput I could expect. The drive advertises 5 GB/s reads and 4.3 GB/s writes.
Using dd if=/dev/zero of=testfile and using various blocksizes and counts to write a 100 GB file, I was able to get about 2.8 GB/s writes. Not quite what the drive had promised in terms of writes, but much better than the 120. I was able to get about 3.2 GB/s reads.
For various reasons (including that while Linux is a fantastic OS in lots of regards, it still sucks on the desktop, especially for my particular needs) I loaded up Windows 10. CrystalDiskMark is a good free benchmark and I was able to test my new NVMe drive there.
I ran it, thinking I’d get the same results from Linux. Nope!
2019-09-14_15-37-09
I got pretty much what the drive promised.
As a comparison, here’s how my old SATA SSD fared:
2019-09-14_15-44-14
About 10x performance. Here’s a couple of takeaways:
PCIe 4 does matter for storage throughput. Would I actually notice in my day-to-day operations the difference between PCIe 3 and PCIe 4? Probably not. But I’m working with 4K video and some people are already working with 6K and even 8K video, that’s not too far down the line for me.
SATA is dead for SSD storage. The new drives are more than capable of utterly overwhelming SATA 3 (600 MB/s, LOL).  Right now, SATA is sufficient for HDDs, but as platters get bigger sequential reads will continue to climb.
I don’t doubt that Linux can do the same, it’s just my methodology failed me. The dd command from /dev/zero had never failed to be the best way to test write speeds for HDD and SATA SSDs, but now I need to find another method for Linux (or perhaps there is some type of bottleneck in Linux).
TL;DR
New PCIe 4 NVMe SSDs are super fast and can be had for a relatively low amount of money ($180 USD for 1 TB). They’re insanely fast.
I need a new way to benchmark Linux storage.

from The Data Center Overlords https://datacenteroverlords.com/2019/09/16/wow-nvme-and-pcie-gen-4/

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