On 23/11/2020 16:49, Frank Bures wrote: > On 11/23/20 10:46 AM, Simon Matter wrote: >>> Hi, >>> >>> I want to replace my hard drives based SW RAID-1 with SSD's. >>> >>> What would be the recommended procedure? Can I just remove one drive, >>> replace with SSD and rebuild, then repeat with the other drive? >> >> I suggest to "mdadm --fail" one drive, then "mdadm --remove" it. After >> replacing the drive you can "mdadm --add" it. >> >> If you boot from the drives you also have to care for the boot loader. I >> guess this depends on how exactly the system is configured. > If you can the new disks while the original 2 disks are still available then grow, add, wait, fail, remove, shrink. That way you will never loose redundancy... # grow and add new disk mdadm --grow -n 3 /dev/mdX -a /dev/... # wait for rebuild of the array mdadm --wait /dev/mdX # fail old disk mdadm --fail /dev/sdY # remove old disk mdadm /dev/mdX --remove /dev/sdY # add second disk mdadm /dev/mdX --add /dev/... # wait mdadm --wait /dev/mdX # fail and remove old disk mdadm --fail /dev/sdZ mdadm /dev/mdX --remove /dev/sdZ # shrink mdadm --grow -n 2 /dev/mdX peter