On 07/05/20 20:36, David F wrote: > I'm planning to use use three mdadm commands to accomplish the > reshape, as follows: > > mdadm --grow --size=6000G --assume-clean /dev/md0 > mdadm --grow --array-size=12000G /dev/md0 > mdadm --grow --raid-devices=3 --backup-file=/root/md-backup /dev/md0 > > > Ideally, I'd prefer a single command, > mdadm --grow --size=6000G --raid-devices=3 /dev/md0 > ... but that seems not possible [1]. > > > In either case, my question still applies: when reshaping to > reduce the number of devices in the array (--raid-devices), is > there any way to specify exactly which device(s) are to be > removed from active sync (I suppose they become spares) and which > ones kept? You should be able to stick --remove /dev/sdX on the command line ... BUT. Before you start, what version of mdadm are you running? The latest? What version of linux? An old LTS with a heavily patched frankenkernel? You really want to be running both a recent kernel and recent mdadm. The other point, if you don't need --backup, DON'T USE IT. It doesn't do any real harm provided you use it right, but it shouldn't be necessary and it causes needless confusion and trouble. Cheers, Wol
