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From: Nikolay Borisov <nborisov@suse.com>
To: Daniel Pocock <daniel@pocock.pro>, linux-btrfs@vger.kernel.org
Subject: Re: 64k and 4k page size inter-op?
Date: Mon, 14 Sep 2020 10:06:58 +0300
Message-ID: <b83c6955-4dc1-4e1f-fb27-8fb9f5b1d2c0@suse.com> (raw)
In-Reply-To: <01a71119-f662-e559-534b-82a6d9fc79f4@pocock.pro>



On 14.09.20 г. 1:49 ч., Daniel Pocock wrote:
> 
> I recently ran into trouble moving btrfs volumes between an amd64 host
> (4k page size) and powerpc64el (64k page size)
> 
> As far as I can tell, the only option to ensure compatibility between
> the two hosts is to
> 
> a) recompile the powerpc64el kernel for a 4k page size,
> 
> b) re-format any volumes created with 64k sectorsize so they have 4k instead
> 
> Is there any other reasonable way to proceed?
> 
> Are there any downsides to using the 4k page size on powerpc64el?

There is currently work underway to allow btrfs to work with subpage
blocksizes i.e being able to mount a 4k filesystem on a 64k page
filesystem. Currently you cannot do this so as you correctly deduced -
you'd have to either equalize the page sizes of both systems or wait
until this work lands in upstream.

> 
> Regards,
> 
> Daniel
> 

  reply index

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-13 22:49 Daniel Pocock
2020-09-14  7:06 ` Nikolay Borisov [this message]
2020-09-14  7:19   ` Daniel Pocock

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