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From: Konstantinos Skarlatos <k.skarlatos@gmail.com>
To: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Cc: linux-btrfs@vger.kernel.org, Hugo Mills <hugo@carfax.org.uk>
Subject: Re: Adding a 4TB disk to a 2x4TB btrfs (data:single) filesystem and balancing takes extremely long (over a month). Filesystem has been deduped with bees
Date: Sat, 2 Apr 2022 21:27:00 +0300	[thread overview]
Message-ID: <67609646-f896-4e69-5246-147a37ccf271@gmail.com> (raw)
In-Reply-To: <YkcIIFuxqj5l17Nu@hungrycats.org>

On 1/4/2022 5:11 μμ, Zygo Blaxell wrote:
> As Hugo pointed out, it's not necessary to balance more than a few
> block groups in this situation.  You have to ensure that the amount
> of unallocated space on all the disks is large enough to contain one
> mirror copy of the metadata.  For most users that means at most 0.5%
> unallocated on each disk.  If you've already balanced 9% of the disk
> then you've already done 18x more balancing than needed and you can
> stop now.
Thank you for your answer. I guess that this should be documented 
somehow in the wiki or the btrfs balance command or even better make a 
"btrfs balance-after-device-add" command that does the right thing 
because now it is very easy to assume that after adding a device one 
should wait for the complete
balance to finish.



  reply	other threads:[~2022-04-02 18:25 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-01 11:13 Adding a 4TB disk to a 2x4TB btrfs (data:single) filesystem and balancing takes extremely long (over a month). Filesystem has been deduped with bees Konstantinos Skarlatos
2022-04-01 13:17 ` Hugo Mills
2022-04-03 13:43   ` Konstantinos Skarlatos
2022-04-01 14:11 ` Zygo Blaxell
2022-04-02 18:27   ` Konstantinos Skarlatos [this message]
2022-04-02 23:16     ` Zygo Blaxell

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