Hello I would like to know which is the correct way ... or the most recommended way to present the disks to ASM, for example: I have 3 disks mapped to a server (rhel7) orasys, orafra, oradata, with dm-multipath I configure the multipath and I put aliases (orasys, orafra and oradata respectively). The doubt I have from there, I have read in the guides, that the disks are formatted, leaving for examples: orasys1, orafra1, oradata1 and these are the ones that are presented to ASM as /dev/mapper/* and with the respective permissions ... but when I do it that way it gives an error finishing the installation of the grid because it cannot create the diskgroup, however if I do not format them, that is, I present them directly as orasys, orafra and oradata I have no problem. The database is oracle 19c and I don't use asmlib but udev rules. Thanks.
How did you "format" them? Oracle expect them to be block devices, not formatted with a file system. Did you read this documentation?