Hi list, I'm new with UEFI and GPT. For several years I've used MBR partition table. I've installed my system on software raid1 (mdadm) using md0(sda1,sdb1) for swap, md1(sda2, sdb2) for /, md2 (sda3,sdb3) for /home. From several how-to concerning raid1 installation, I must put each partition on a different md devices. I've asked times ago if it's more correct create the md device, partitioning it and create fs on each partition created on md device: mdadm create /dev/md0 ... fdisk /dev/md0: md0p1 swap md0p2 / xfs md0p3 /home xfs or create for each partition an md device and create the fs on mdX device directly: mdadm create /dev/md[012]..... mkfs.fs /dev/mdX (for each md device) md0 swap md1 / md2 /home I got as answer that the second solution is the correct solution. I'm installing C7 1511 on a skylake machine with UEFI and I'm confused. After googling, for my installation I must create gpt table, 1 partition with fat32 type of 512M, and 2 partition for swap and / (I've excluded /home), clone gpt partition table on second disk with sgdisk, create md device for swap and /. I've created gpt partition table with: 1) part1 512m fat32 EFI-part 2) part2 8gb raid swap 3) part3 ~500gb raid / then I've cloned gpt of sda to sdb without problem. Then I've created array md0 for swap and md1 for / and then rebooted the system. I've started installation process. During disk selection I get only one disk tagged as MDRAID disk and not sda and sdb. Selecting MDRAID disk I can't see sda1 sdb1 EFI-part, md0 and md1 devices. Going to console, cat /proc/mdstat give me only md1. If I try to start md0 mdadm says sda2: not such file or directory but the partition exists on /dev/sda. Coming back to Installer, it forces me to create partitions on MDRAID (md1) disk and I create: md1p1 EFI md1p2 swap md1p3 / Installation was performed an system booted. Now, on this machine with mbr partition type I get md0 (sda1, sdb1) and md1 (sda2, sdb2) on uefi machine with gpt I get md1 (sda, sdb). I've tried also installing with mbr before using gpt, and I got md0 (sda1, sdb1), md1(sdb2, sda2) and the other 2 partition for EFI as expected. But with mbr installer said me that It gpt was needed. Why using gpt, if I set two raid partition, create 2 raid, rebooting it gives me that md1 has sda and sdb instead sda2 and sdb2 and other md is dead? What is the correct method to install on RAID? 1 md device and create partition on it or N md devices for N partition? Why using gpt I get only one disk on disk selection (mdraid device), not the 2 physical disk, and not the 2 md raid created? Hope in help. Alessandro.