Once upon a time, hw hw@gc-24.de said:
Are you saying there is no difference between a RAID1 and a non-raid device as far as xfs is concerned?
Yes.
What if you use hardware RAID?
No difference - same result.
When you look at [1], it tells you to specify su and sw with hardware RAID and says it detects everything automatically with md-RAID. It doesn´t have an example with RAID1 but one with RAID10 --- however, why would that make a difference?
Because RAID level 1 and RAID level 10 are different. I suggest you read:
https://en.wikipedia.org/wiki/RAID#Standard_levels
What is called "RAID 10" is really a combination of level 1 and level 0 (which one is higher/lower varies between implementations).
If you read from both disks in a RAID1 simultaneously, you have to wait out the latency of both disks before you get the data at full speed, and it might be better to use stripes with them as well and read multiple parts of the data at the same time.
RAID level 1 has the same data on both drives. You wouldn't be reading the same data from both drives at the same time; reads would be spread between the drives (I know the Linux software RAID tries to keep read load fairly balanced between drives, I assume most hardware RAID implementations do the same).
Oh, ok. How do you know what stripe size was picked by mdadm? It seemd a good idea to go with defaults as far as possible.
Again, RAID level 1 has no stripes.