Optimal SSD Pool configuration with 4 Drives

[johnnytcpa]

This should be a quick question.

 

I plan to have 1 ZFS SSD Pool with 1 parity to permanently store [appdata, VMs, SMB, etc] in FAST storage and another cache pool for regular media downloading and anything else that will be moved to array.

 

I have the following SSDs with the following endurance (TBW)

• 2X 2TB SN850X Gen 4 SSD @ 1200TBW
• 2TB SN850 Gen 4 SSD @ 1200TBW
• 2TB Intel 670p Gen3 SSD @ 740 TBW

 

Since the Intel 670p has lower write endurance (and much lower speeds) than the other 3 drives I have, which would be the best configuration (examples below).

Option 1: ZFS RaidZ1 pool: 2x SN850X w/ SN850 as parity AND Cache Drive: Intel 670p

Option 2: ZFS RaidZ1 pool: 2x SN850X w/ Intel 670p as parity AND Cache Drive: SN850

Option 3: ZFS RaidZ1 pool: SN850X + SN850 w/ SN850X as parity AND Cache Drive: Intel 670p

 

[itimpi]

I think you have misunderstood how ZFS works.    In ZFS pools the parity information is striped across the drives in the pool and not to a dedicated parity drive.   

[johnnytcpa]

On 7/23/2023 at 3:25 PM, itimpi said:

I think you have misunderstood how ZFS works.    In ZFS pools the parity information is striped across the drives in the pool and not to a dedicated parity drive.   

Thanks. I am new to ZFS/RAID. 

 

I was basing my basic understanding on RAIDZ5 and assumed ZFS works similarly. In a sense, if I don't dedicate a parity drive in my ZFS pool, would that mean it will automatically run at the slowest speed drive (SN850)? 

[JorgeB]

If you create a ZFS raidz pool (and not use the devices in the array) the pool speed will be limited by the slowest device.