On 04/25/2014 12:12 PM, Austin S Hemmelgarn wrote:
On 2014-04-25 13:24, Chris Murphy wrote:
On Apr 25, 2014, at 8:57 AM, Steve Leung <[email protected]> wrote:
I've got a 3-device RAID1 btrfs filesystem that started out life as
single-device.
btrfs fi df:
Data, RAID1: total=1.31TiB, used=1.07TiB
System, RAID1: total=32.00MiB, used=224.00KiB
System, DUP: total=32.00MiB, used=32.00KiB
System, single: total=4.00MiB, used=0.00
Metadata, RAID1: total=66.00GiB, used=2.97GiB
This still lists some system chunks as DUP, and not as RAID1. Does this mean
that if one device were to fail, some system chunks would be unrecoverable?
How bad would that be?
Assuming this is something that needs to be fixed, would I be able to fix this by
balancing the system chunks? Since the "force" flag is required, does that
mean that balancing system chunks is inherently risky or unpleasant?
I don't think force is needed. You'd use btrfs balance start -sconvert=raid1
<mountpoint>; or with -sconvert=raid1,soft although it's probably a minor
distinction for such a small amount of data.
The kernel won't allow a balance involving system chunks unless you
specify force, as it considers any kind of balance using them to be
dangerous. Given your circumstances, I'd personally say that the safety
provided by RAID1 outweighs the risk of making the FS un-mountable.
Agreed, I'll attempt the system balance shortly.
Personally, I would recommend making a full backup of all the data (tar
works wonderfully for this), and recreate the entire filesystem from
scratch, but passing all three devices to mkfs.btrfs. This should
result in all the chunks being RAID1, and will also allow you to benefit
from newer features.
I do have backups of the really important stuff from this filesystem,
but they're offsite. As this is just for a home system, I don't have
enough temporary space for a full backup handy (which is related to how
I ended up in this situation in the first place).
Once everything gets rebalanced though, I don't think I'd be missing out
on any features, would I?
Steve
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
