mdadm: add new device failed for /dev/xvdl as 2: Invalid argument

I have existing RAID0 setup with two disks. I have to add a new drive to it. But when I try to run the following command:

mdadm --add /dev/md/customer_upload /dev/xvdl

I get an error:

mdadm: add new device failed for /dev/xvdl as 2: Invalid argument

How do I add a new disk to an existing RAID0?

I used the following steps to create RAID 0 initially:

 sudo mdadm --create --verbose /dev/md/customer_upload --level=stripe --raid-devices=2 device_name1 device_name2

EDIT

Seems like you cannot add disk to RAID0.

I ran the following command and it made it RAID4 How & Why I am still not clear

/dev/md/customer_upload --grow -l 0 --raid-devices=3 -a /dev/xvdl

I can see three disks in RAID4 but total space is still 2Tb

xvdf    202:80   0     1T  0 disk  
└─md127   9:127  0     2T  0 raid4 /customer_upload
xvdg    202:96   0     1T  0 disk  
└─md127   9:127  0     2T  0 raid4 /customer_upload
xvdl    202:176  0     1T  0 disk  
└─md127   9:127  0     2T  0 raid4 /customer_upload

According to the kernel.org RAID wiki:

After the new disk was partitioned, the RAID level 1/4/5/6 array can be grown

that is, RAID-0 is not eligible for growing. You will need to backup all the data, recreate the array from scratch, and restore from backups.

yes you can, to add one disk to raid 0

mdadm --grow /dev/md0 --level=0 --raid-devices=3 --add /dev/sdd

or you can add several disks

mdadm --grow /dev/md0 --level=0 --raid-devices=4 --add /dev/sdd /dev/sde

raid-devices=4 total devices count with new disks, raid 0 become raid 4 and after reshape will be raid 0 again

and these sysctl opts for reshape speed control dev.raid.speed_limit_min and dev.raid.speed_limit_max