Any help ?

Il giorno gio 25 gen 2024 alle ore 15:49 Gandalf Corvotempesta
[off-list ref] ha scritto:

Ok, i think i did a mess.
I have a 3 way mirror with 3 drives on it
All drives are working, not failed.
I would like to replace one of these drive (because it's very old)
with a new drive.
I would like to to the add and replace in the same phase, without
reducing the redundancy level
I did this multiple times before, during the sync, the array is a 4 way mirror

BUT this time i think i did an issue, i've just run this:

$ mdadm /dev/md0 --add /dev/sdd1 --replace /dev/sda1 --with /dev/sdd1

sda was marked failed immediately, and sdd1 is marked as active sync.
Less than 1 second.

Is this ok or i've just added a blank drive and forced the removal of
a working one ?

Honestly, and this is something that comes to mind right now, the
partition is very very small, like 64MB so 1 second sync (on a SSD)
could be ok.

but:
1. which is the right command to run to add-sync-remove a not-failed disk ?
2. how can I ensure that sdd is working as expected and data were
synced properly?