Re: shall distros run btrfsck on boot?

[Jeff Mahoney <jeffm@suse.com>]

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On 11/29/15 8:59 PM, Qu Wenruo wrote:
> 
> 
> Jeff Mahoney wrote on 2015/11/28 11:52 -0500: On 11/23/15 11:02
> PM, Christoph Anton Mitterer wrote:
>>>> Hey.
>>>> 
>>>> Short question since that came up on debian-devel.
>>>> 
>>>> Now that btrfs check get's more and more useful, are the 
>>>> developers going to recommend running it periodically on
>>>> boot (of course that wouldn't work right now, as it would
>>>> *always* check)?
> 
> Running fsck on boot is a holdover from an era where non-journaling
> file systems were the norm.  It persists in the ext* world mostly
> due to inertia, but it shouldn't be run on boot with ext3 or ext4
> either. As Eric noted, fsck.xfs is a no-op.  We have something
> similar for btrfs and have no intention of ever running fsck on
> boot with btrfs except in the case of a mount failure of the root
> file system.
> 
>>>> Plus... is btrfs check (without any arguments) 
>>>> non-desctructive, or are there corner-cases where it may
>>>> lead to any changes on the devices?
> 
> I haven't reviewed it in detail, but a quick glance makes it look 
> like it will, minimally, create transactions even in check-only 
> mode.
> 
>> This seems interesting.
> 
>> Any clue to enhance?

My glance wasn't close enough.  We only start a transaction after we
check and repair is enabled.

- -Jeff

- -- 
Jeff Mahoney
SUSE Labs
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