Hi Gaurav,

If there is a zpool already configured and it is to be extended with a newly added disk, please follow these steps.

1. Set all the disks label to GPT:

    parted /dev/sdX    mklabel gpt 

2. Add disk to zpool using following command:

    zpool add <existing_pool_name> /dev/sdX (X stands for the disk character usually its a,b,c,d,e,f,g,h...)

   If disks are to be added in raidz mode:

    zpool add <existing_pool_name> raidz /dev/sdX1 /dev/sdX2 /dev/sdX3

   If disks are in mirror mode:

  zpool add <existing_pool_name> mirror /dev/sdX1 /dev/sdX2

If an entire disk is in zpool and it is expanded from VM, following command can be used to extend the pool with the expanded space.

   zpool online -e <pool_name> /dev/sdX

If only a partition of a disk is in zpool and it is expanded in VM, a new partition should be created from the expanded portion and added to the zpool.

   zpool add <pool_name> /dev/sdXn 

I hope this will answer your query.