RAIDZ Level and Number of Drives

[rfielder]

What is the general consensus on RAIDZx levels vs number and size of drives?

I have checked the documentation, and it is informative, but does not seem to have a reccommendation.

For a six drive array, it looks like RAIDZ2 is the best balance between safety and free space.

If you go to seven drives? Or eight? At what point should you consider RAIDZ3 instead of RAIDZ2?

At this time, I am building a FreeNAS system with six 8Tb drives. However, I am still evaluating my space requirements, and my need to increase by one or two drives. This will be done before the build is finalized, so all drives will be in on pool from the start.

 

[Mr. Slumber]

What is the general consensus on RAIDZx levels vs number and size of drives?

> 3 drives == raidZ2 or above (most people say: never use raidZ1)

Please take a look here. I found this link thanks to @Chris Moore :)

 

[Heracles]

most people say: never use raidZ1

And I am one of them. RaidZ1 is an illusion of security more than a protection.

There is also the question of IOPS and performance. If you have more drives and need more performance, Raid-10 will serve you better.

It would also be possible to have a few RaidZ vDevs in a single pool. So 10 drives could be 2x 5 drives RaidZ2 vDevs. More vDevs increases the IOPS.

There is no silver bullet here and a review of the needs and conditions is required to design a propre pool.