Hi, I'm regularly using software RAID for my CentOS storage servers, either with RAID 1 or RAID 6 depending on the number of disks. Here's two questions about mdadm I've always been wondering about. 1. I'm not sure about the --metadata option. Let's say I want to create a simple RAID 1 setup, I'm usually doing it like this: # mdadm --create /dev/md/boot --level=1 --raid-devices=2 \ --metadata=1.2 /dev/sda1 /dev/sdb1 If anyone can explain the exact meaning of --metadata, I'd be grateful. Oh, and is it OK to use --metadata=1.2 in CentOS 7.x and 8.x ? 2. I'm regularly encountering the mdadm --misc option in various tutorials on the Internet. I looked it up in mdadm's manpage, but it doesn't seem to be documented. Any idea what this option does ? Cheers, Niki -- Microlinux - Solutions informatiques durables 7, place de l'église - 30730 Montpezat Site : https://www.microlinux.fr Blog : https://blog.microlinux.fr Mail : info at microlinux.fr Tél. : 04 66 63 10 32 Mob. : 06 51 80 12 12