Can I add additional disks to an existing pool/vdev that is mirrored?

[cincibcat9]

I currently have a pool that has mirrored 4TB drives. Is it possible to added a pair of mirrored disks to the original pool/vdev?

This is my current setup:

 

[spuky]

yes just click the cog on the right and "add vdev" you then can select 2 disks and add them as another mirror...

 

[ChrisRJ]

Please have a look at the recommended readings in my signature. They should provide you with a lot of background information.