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Confusing output of btrfs fi df

DISCUSSION Stefan Malte Schumacher 2 participants 2 messages Apr 28, 2014 Btrfs file system

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#0 lore raw
Quoted 4 lines

So try this one:
btrfs balance start -musage=0 -v

I fear that didn't work too.

mars:/mnt # btrfs balance start -musage=0 -v btrfs/ Dumping filters: flags 0x6, state 0x0, force is off
METADATA (flags 0x2): balancing, usage=0 SYSTEM (flags 0x2): balancing, usage=0 Done, had to relocate 1 out of 2708 chunks

mars:/mnt # btrfs fi df btrfs/
Data, RAID1: total=2.64TiB, used=2.22TiB
System, RAID1: total=8.00MiB, used=380.00KiB
System, single: total=4.00MiB, used=0.00
Metadata, RAID1: total=4.00GiB, used=2.94GiB

Quoted 2 lines

If that fails to remove the extra system chunk, then we have a mystery indeed. What's different on your system and why isn't it working?

I have no idea. Its just a plain openSUSE 13.1 and they consider btrfs support stable enough to use it as default filesystem in the upcoming 13.2. I could create the filesystem again and restore the data but of course I would actually need to know what went wrong the first time in order to avoid doing it again. Is there anything you need to know about my system which would be of use? (Controller, Disks, Mainboard etc. ?)

Yours sincerely
Stefan

#1 lore raw
Quoted 23 lines · Stefan Malte Schumacher
Quoted 4 lines

So try this one:
btrfs balance start -musage=0 -v

I fear that didn't work too.

mars:/mnt # btrfs balance start -musage=0 -v btrfs/ Dumping filters: flags 0x6, state 0x0, force is off
METADATA (flags 0x2): balancing, usage=0 SYSTEM (flags 0x2): balancing, usage=0 Done, had to relocate 1 out of 2708 chunks

mars:/mnt # btrfs fi df btrfs/
Data, RAID1: total=2.64TiB, used=2.22TiB
System, RAID1: total=8.00MiB, used=380.00KiB
System, single: total=4.00MiB, used=0.00
Metadata, RAID1: total=4.00GiB, used=2.94GiB

Quoted 2 lines

If that fails to remove the extra system chunk, then we have a mystery indeed. What's different on your system and why isn't it working?

Quoted 7 lines

I have no idea. Its just a plain openSUSE 13.1 and they consider btrfs support stable enough to use it as default filesystem in the upcoming 13.2. I could create the filesystem again and restore the data but of course I would actually need to know what went wrong the first time in order to avoid doing it again. Is there anything you need to know about my system which would be of use? (Controller, Disks, Mainboard etc. ?)

The question is, why is this important?

The presence of that area won't affect the operation of the FS in
the slightest. The FS won't write any data to that area, and it's only 4MiB in size -- completely lost in the noise for a 2.6 TiB filesystem. At worst, it's an extra line of output; slightly messy, but utterly harmless.

I think the default kernel for OpenSuSE 13.1 is 3.11, which may be
old enough that it doesn't have the patch that allows balancing of chunk 0 (which is probably what's happening here).

Hugo.

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