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From: Qu Wenruo <quwenruo.btrfs@gmx.com>
To: dsterba@suse.cz, Forza <forza@tnonline.net>,
	linux-btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: Select DUP metadata by default on single devices.
Date: Mon, 20 Sep 2021 19:26:38 +0800	[thread overview]
Message-ID: <a9b4ce46-27a2-377a-3c36-7706d71daf28@gmx.com> (raw)
In-Reply-To: <20210920112349.GE9286@twin.jikos.cz>



On 2021/9/20 19:23, David Sterba wrote:
> On Mon, Sep 20, 2021 at 06:46:31PM +0800, Qu Wenruo wrote:
>>> - single by default for data on multiple devices (now it's raid0)
>>
>> Is there any discussion/thread on that part?
>>
>> As I'm not that aware about this.
>
> It's been discussed on IRC long time ago. The problem with raid0 is that
> it's a striped profile and changing to another profile may be
> problematic once all the chunk space is alloated. Unlike for single
> where it's on just one device and converting to anything is easy.
>
> I think that for multi-device fs everybody specifies the profiles
> manually anyway, but the defaults should be sane.

OK, that makes completely sense.

Then I have no concern for the switch so far.

Thanks,
Qu

>
>>> - free-space-tree on
>>> - no-holes on
>>>
>>> I'd vote for one version doing the whole switch rather than doing the
>>> changes by one.
>>
>> I'm fine on DUP and FST.
>>
>> On no-holes I'd prefer more feedback from Filipe as he has exposed some
>> no-holes related problem some time ago.
>
> Yeah I know Filipe is not all happy about making no-holes default, it
> removes some capabilities of 'check' to verify extents. Some bugs have
> been fixed recently (kernel side) but that's IMO on par with regular bug
> hunting & fixing.
>
> I don't know when would be the perfect time to make no-holes dfault,
> it's a feature to reduce metadata consumption which is IMO worth as FST
> will increase it again. Backward compatibility is good, lots of stable
> versions support it.
>

  reply	other threads:[~2021-09-20 11:26 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-18 21:38 Select DUP metadata by default on single devices Forza
2021-09-18 23:58 ` Qu Wenruo
2021-09-20  3:32   ` Chris Murphy
2021-09-19 12:19 ` Su Yue
2021-09-20  9:09 ` David Sterba
2021-09-20 10:46   ` Qu Wenruo
2021-09-20 11:23     ` David Sterba
2021-09-20 11:26       ` Qu Wenruo [this message]
2021-09-20 11:38         ` David Sterba
2021-09-20 11:30     ` David Sterba
2021-09-20 11:12   ` Steven Davies
2021-09-20 11:32     ` David Sterba

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