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I'm trying to convert a 2 drive btrfs array on Ubuntu 12.04 to use RAID1. Following the instructions on the btrfs wiki I've tried this command, with no success:

valorin@gimli:~$ sudo btrfs filesystem balance start -dconvert=raid1 -mconvert=raid1 /
ERROR: 'filesystem balance' requires 1 arg(s)

I've checked for documentation, but I can't seem to find any documentation for this command.

Any ideas what I'm doing wrong?

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For future reference, converting is now (in current versions) done using the balance subcommand (without "filesystem"), so it would be: btrfs balance start -dconvert=raid1 -mconvert=raid1 /mnt – basic6 Oct 20 '15 at 19:09
up vote 1 down vote accepted

To use the extra arguments with the balance command, you need to install a newer version of btrfs-tools than is available for Ubuntu 12.04.

It's pretty easy (see first answer) to compile a new version of btrfs-tools from the btrfs git repo. There are also binary packages from Debian sid or Ubuntu 12.10 that might work.

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