On 2017-07-24 10:12, Cloud Admin wrote:
Am Montag, den 24.07.2017, 09:46 -0400 schrieb Austin S. Hemmelgarn:
On 2017-07-24 07:27, Cloud Admin wrote:
Hi,
I have a multi-device pool (three discs) as RAID1. Now I want to
add a
new disc to increase the pool. I followed the description on https:
//bt
rfs.wiki.kernel.org/index.php/Using_Btrfs_with_Multiple_Devices and
used 'btrfs add <device> <btrfs path>'. After that I called a
balance
for rebalancing the RAID1 using 'btrfs balance start <btrfs path>'.
Is that anything or should I need to call a resize (for example) or
anything else? Or do I need to specify filter/profile parameters
for
balancing?
I am a little bit confused because the balance command is running
since
12 hours and only 3GB of data are touched. This would mean the
whole
balance process (new disc has 8TB) would run a long, long time...
and
is using one cpu by 100%.
Based on what you're saying, it sounds like you've either run into a
bug, or have a huge number of snapshots on this filesystem.
It depends what you define as huge. The call of 'btrfs sub list <btrfs
path>' returns a list of 255 subvolume.
OK, this isn't horrible, especially if most of them aren't snapshots
(it's cross-subvolume reflinks that are most of the issue when it comes
to snapshots, not the fact that they're subvolumes).
I think this is not too huge. The most of this subvolumes was created
using docker itself. I cancel the balance (this will take awhile) and will try to delete such of these subvolumes/snapshots.
What can I do more?
As Roman mentioned in his reply, it may also be qgroup related. If you run:
btrfs quota disable
On the filesystem in question, that may help too, and if you are using
quotas, turning them off with that command will get you a much bigger
performance improvement than removing all the snapshots.
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