It's 5 slow disks, 2 medium and one fast. Please explain how the faster disks can be an issue? In my experience the only performance issue is that the RAID will be held back by the slower disks.
If some faster disks actually were a problem, I would expect both RAID 6 and 10 to suffer pretty much equally from it. Data need to be written to all disks (including the slow ones) in both cases before the test can finish.
You have those numbers and every other RAID 6 and RAID 0 configuration possible in an 8-bay in the post where I showed the results of my testing.can you try same test but only first 7 drives in RAID ...
No. I did those tests months ago and it took probably two weeks with all the rebuilds necessary. That system is now in production and I won't take it down again for even more testing.and if using ``dd`` please try ``bs=4k`` , 8k, 64k, and 128k, ...
I have testing that support my position in the discussion, that at least with mechanical disks RAID 6 is faster when doing sequential writes with a decent CPU from 6 disks and up. Now please show us testing that support your position, that RAID 10 is always significantly faster.
The ARM CPUs aren't exactly known for being the most powerful CPUs on the planet...algebra should be the same ... ... implementation can be the wrong .. but from what i got on ts1231 i ts1232 both 12xSSD 1|TB and 12x8TBHDD ... it is way faster raid 10
With SSDs in particular, I think it's logical that the CPU become much more of a factor than with mechanical disks. Maybe you need a Ryzen to handle SSDs in RAID 6 better or maybe not even that is enough? I don't know as I don't have the amount of SSDs necessary for testing.
That in enterprise storage the disks used are normally much faster (SSD and SAS) may also be an explanation to why enterprise storage truths don't always apply on home and SMB NAS usage with larger numbers of mechanical SATA disks.
As you can see in the other test I linked, with mechanical disks a Celeron G550 (Passmark 2290) is enough for RAID 6 to be faster from 6 mechanical disks and up.