Hi, My apologies - I read and replied late last night without reading properly. On 17/06/2012, at 10:27 PM, Russell Coker wrote:
# mkfs.btrfs -m raid1 -d raid1 /dev/sdX
That works if you have empty disk space. But if you are converting from ext3/4 then mkfs isn't the option.
You're right. In order to do what you want, you would do a btrfs-convert on a single disk, which would result in a default btrfs filesystem, i.e. duplicated metadata, single data. Once you're happy with that, you can then add the other disk to the btrfs filesystem: # btrfs device add /mount/ After both devices are in the filesystem, rebalance to copy chunks across all devices: # btrfs balance start /mount/ Though, you want to get the rebalance engine to change the layout, so you can use the convert option: # btrfs balance convert raid1 /mount/ Check the cmd_balance.c source for verify this command and check the options. I'm betting your ability to read C is better than mine: http://git.kernel.org/?p=linux/kernel/git/mason/btrfs-progs.git;a=blob;f=cmd...
is, is it worth the pain of running an Oracle kernel with Debian for the newer BTRFS code?
The current Oracle release code is probably at the same point as the 3.2 kernel, so this is probably not necessary. When do a major btrfs mainline merge in a few months, it may be useful.
Also I'll probably install some systems with Oracle Dom0 and Debian DomUs, that should be easy to setup and manage.
Actually, I would probably reverse this: use a Debian Dom0 with Oracle DomUs. The only supported Oracle Dom0 is Oracle VM, for which we do not provide 0-day updates via public-yum (only ULN, which requires a support subscription). Also, Oracle VM 3.1.1 requires an Oracle VM Manager install, which usually implies another machine (or a VM somewhere else). However, you can run Oracle Linux as a HVPVM or PVM guest of any Xen/Dom0 combination you already have.