Netapp Converting a Spare disk as a Data Disk

Converting a Spare disk as a Data Disk

I was confused on the situation when I have2 spare disks in the pool. But my aggr need more data space.

I run aggr add and got warning. I quit!!!

FAS786> aggr add aggr1 -d 0a.26 0a.42        

                                           

WARNING! Continuing with aggr add will result in a
low spares disk condition for one or more RAID groups.
Are you sure you want to continue with aggr add? n

I think it need spare disks in the pool. So how many spare disks it need? I have 2 Disk shelf, so I think maybe 2 spares.

At last, I tried add one disk, it succeed.

FAS786> aggr add aggr1 -d 0a.26     

Addition of 1 disk to the aggregate has completed.

So I think it is better left one spare for pool.

So i can conclude that at least i need to have one spare disk per pool.