@olivierlambert couldn't open /Dev/sda for write - not zeroing

Tried:
mdadm --stop /dev/md127

Result:
Cannot get exclusive access to /dev/md127
Perhaps a running process, mounted filesystem or active volume group?

I will try with DD now

@frank-s, very thanks for the help!
where I run this line? on shell option at xcp-ng instalation screen, or f3 when installing, or using another live linux?

@frank-s newbie here, just 1 week of trying to use, have that exactly same problem, already make raid, did some things, when trying to install again, md127p1 is already in use, I know need the zero raid... But I don't know how.... Using another live Linux?

@olivierlambert
Just to solve a doubt.... there is no way to install xcp-ng on software RAID 10, right?

Hello everybody! Newbie here, just 24h of xcp use, I was trying set Raid 10, but xcp only support Raid 1, so I'm trying now to set raidz, like on the document, I'm using 4 disks (500gb each), but I want to do Raid on this 4 disks (sda,sdb,sdc,sdd), so I can't? Need to be 6 disks? 2 raid 1 with xcp, and 4 raidz for other things?