I want to create a 1 TB Raid array with SSDs. I think about using Raid 5 or Raid 1.
I've read a lot of articles regarding SSD in Raid 5, i.e. What are the main points to avoid RAID5 with SSD? . Most answers are "don't use SSDs with Raid 5, Raid 5 reduces the lifetime of your SSD. Raid 1 is great".
Is this really true ? Here my thoughts:
Raid 5: Raid 5 with 3 disks:
To store some data you need read old data from disk (A) store new data on disk (B) and to store parity data on disk (C).
If you use i.e. Samsung 850 Evo SSDs with 500 GB you can write up to 150 TB (from Samsung datasheet).
If you write 150 TB user data in Raid 5 setup you have to write 150 TB additional parity data, at all 300 TB to all three disks. This is 100 TB per disk.
That means you reached 66% of maximum specified writes (100/150 TB).
Raid 1: Raid 1 with 2 disks
If you use i.e. Samsung 850 Evo SSDs with 1 TB capacity you can write up to 150 TB (from Samsung datasheet).
If you write 150 TB in Raid 1 setup you'll write at all 300 TB to both disks, and 150 TB per disk.
That means you reached 100% of maximum specified writes (150/150 TB).
So I would say, Raid 5 in this setup is better. Did I make a mistake ?
Kind regards Mr. Digit