Am Samstag, 24. Januar 2015, 15:46:22 schrieb Daniel Pocock:
> On 24/01/15 15:36, Hugo Mills wrote:
> > On Sat, Jan 24, 2015 at 03:32:44PM +0100, Daniel Pocock wrote:
> >> I've got a RAID1 on two 1TB partitions, /dev/sda3 and /dev/sdb3
> >>
> >> I'm adding two new disks, they will have bigger partitions
> >> /dev/sdc3 and /dev/sdd3
> >>
> >> I'd like the BtrFs to migrate from the old partitions to the new
> >> ones as safely and quickly as possible and if it is reasonable to
> >> do so, keeping it online throughout the migration.
> >>
> >> Should I do the following:
> >>
> >> btrfs device add /dev/sdc3 /dev/sdd3 /mnt/btrfs0 btrfs device
> >> delete /dev/sda3 /dev/sdb3 /mnt/btrfs0
> >>
> >> or should I do it this way:
> >>
> >> btrfs device add /dev/sdc3 /mnt/btrfs0 btrfs device delete
> >> /dev/sda3 /mnt/btrfs0 btrfs device add /dev/sdd3 /mnt/btrfs0
> >> btrfs device delete /dev/sdb3 /mnt/btrfs0
> >>
> >> or is there some other way to go about it?
> >
> > btrfs replace start /dev/sda3 /dev/sdc3 /mountpoint btrfs fi resize
> > 3:max /mountpoint btrfs replace start /dev/sdb3 /dev/sdd3
> > /mountpoint btrfs fi resize 4:max /mountpoint
> >
> > The 3 and 4 in the resize commands should be the devid of the
> > newly-added device.
>
> Thanks for the fast reply
>
> In the event of power failure, can I safely shutdown the server during
> this operation and resume after starting again?
>
> I get more than 2 hours runtime from the UPS but I suspect that
> migrating 1TB will take at least 12 hours.
You can at least cancel the replacing:
merkaba:~> btrfs replace --help
usage: btrfs replace <command> [<args>]
btrfs replace start [-Bfr] <srcdev>|<devid> <targetdev> <mount_point>
Replace device of a btrfs filesystem.
btrfs replace status [-1] <mount_point>
Print status and progress information of a running device replace
btrfs replace cancel <mount_point>
Cancel a running device replace operation.
I thought you could resume it then later, but I don't see this. The man
page doesn't see it either.
--
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7
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