On 23/11/2020 17:16, Ralf Prengel wrote:
Backup!!!!!!!!
Von meinem iPhone gesendet
You do have a recent backup available anyway, haven't you? That is: Even without planning to replace disks. And testing such strategies/sequences using loopback devices is definitely a good idea to get used to the machinery...
On a side note: I have had a fair number of drives die on me during RAID-rebuild so I would try to avoid (if at all possible) to deliberately reduce redundancy just for a drive swap. I have never had a problem (yet) due to a problem with the RAID-1 kernel code itself. And: If you have to change a disk because it already has issues it may be dangerous to do a backup - especially if you do a file based backups - because the random access pattern may make things worse. Been there, done that...
peter
Am 23.11.2020 um 17:10 schrieb centos@niob.at:
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