How do I verify which pool layout I am using?

[Gimpymoo]

I have checked my Zpool status but am unable to fathom what it is saying.

I can obviously see there are 2 mirrors, so does that mean I have 2 disk redundancy or am I misunderstanding?

Any guidance appreciated, thank you.

 

[HoneyBadger]

Welcome.

What you have are two mirror vdevs of two disks each. Each vdev can survive a single drive failure.

Those two vdevs are then striped together to make up your pool.

So you can lose one disk from each vdev - but not two disks from one.

 

[gpsguy]

you have "striped mirrors".

The redundacy is per vdev. Each of your mirrors is one vdev. You can loose one disk in either set pf mirrors. If you loose 2 disks in a single mirror, you'll lose your pool.

 

[Gimpymoo]

Thank you both for the replies.

I should have gone with RAIDZ2 I think, that would mean that any two disks could fail and I still have data?

As I understand it, there are performance benefits of striped mirrors compared to RaidZ2 right but in my situation, would rather have the protection against failure above performance.

In terms of "cost", I have half of the total space available to me, RaidZ2 would be no worse.

I assume that to change pool layout, I need to delete the pool and start again or is there another way?

Current setup is 4 x 3TB disks... only about 500GB usage at present.

 

[HoneyBadger]

Correct on all assumptions, unfortunately including the need to destroy the pool to change vdev configuration in this way.

Thankfully with only 500GB used, "backup, recreate, restore" is hopefully still a viable option.

 

[Stux]

The other benefit of striped mirrors is you can easily stripe in a 3rd mirror.

 

[HoneyBadger]

The other benefit of striped mirrors is you can easily stripe in a 3rd mirror.

Whether you're talking about a third vdev in the pool, or a third disk in each vdev - yes, that is an advantage.