RAID 0 with 3 drives only has 2x performances
Thanks for investigating, looking forward to your findings!
To summarize: RAID4/5 with 4x SSDs in Thunderbay 4 Mini enclosure. Expected performance 2-3x writes, 3x reads:
- M1, macOS 12.2.1: 1.5x writes, 2x reads (with occasional 0.75x writes that can be alleviated by connected an additional Thunderbolt cable)
- i9, macOS 12.2.1: 1.75x writes, 2x reads
While M1 is a bit slower (and occasionally much slower writes with one cable), the i9 also fails to reach the expected performance. So there is an M1 specific TB issue but also a general performance issue affecting intel cpus as well.
In which OS/hardware setting do you actually get the 2-3x writes + 3x reads performance with a Thunderbay enclosure?
If I understand the response from OWC tech support correctly, RAID4 is not expected to perform above 2x single drive performance. They linked the following benchmark results ( https://eshop.macsales.com/item/OWC/TB3QMSRS08TP/#benchmarks)
which corresponds to ~1.8x write and ~2.1 reads (on an intel cpu). The difference to what I get can probably be attributed solely to the M1 cpu.
I also did not observe drops to ~0.75x writes anymore since I filled the RAID and connected it via a single cable to a Thunderbolt hub (but I am glad you could reproduce the issue).
Please let me know if you can give any recommendations on how to increase speeds (in particular achieving 3x read speeds, which was my expectation when purchasing the setup).
I am working on this. I have a table of results for engineering to review. Plus, some results with M1 where performance changed (lower) from earlier tests, and I am unclear what the difference was.
It's been a month, any updates?
I have been running other benchmarks, with NVMe blades, where RAID 4 generates >2000 writes, 2300 reads. The Mini and TB4 enclosures go through PCI, so will be much slower. I have the system set up, I can run a quick test on an M1 Air with 4 SSDs today
I did find some strange anomalies when testing on M1, which I reported to hardware engineering, and I so not know what the result is yet.
Just ran some tests on an M1 air and M1 Max (similar results.
OWC Mercury Extreme Pro 6G, 1TB SSD drives in a Thunderbay (2 and 3 give similar results)
I ran AppleRAID RAID 0, SoftRAID RAID 0 and SoftRAID RAID 4
AppleRAID and SoftRAID gave the same results, close to 1400 writes, 1500 reads.
SoftRAID RAID 4 was around 1000 writes, 1150 reads.
Most likely PCI is the reason, as NVMe, which bypass PCI, give much faster results.