From: Roman Kapusta <roman.kapusta@gmail.com>
To: Fabian Zeindl <fabian.zeindl@gmail.com>
Cc: Martin Steigerwald <Martin@lichtvoll.de>,
linux-btrfs@vger.kernel.org, Hugo Mills <hugo@carfax.org.uk>
Subject: Re: Why does Btrfs allow raid1 with mismatched drives? Also: How to look behind the curtain
Date: Thu, 5 Jan 2012 14:35:00 +0100 [thread overview]
Message-ID: <CABVOS0_3O8qZTEOuAvdbsCKfMJNKYS1C0dU2CL5=h5MVSWDe+A@mail.gmail.com> (raw)
In-Reply-To: <82FEA956-FFE4-4A00-B895-AA381A35FEE7@gmail.com>
On Thu, Jan 5, 2012 at 13:26, Fabian Zeindl <fabian.zeindl@gmail.com> w=
rote:
>
> On Jan 5, 2012, at 11:39 , Martin Steigerwald wrote:
>> "Allocating as many chunks as can fit across the drives" is also pre=
tty
>> clear to me. So if BTRFS can=C2=B4t allocate a new chunk on two devi=
ces, its
>> full. To me it seems obvious that BTRFS will not break the RAID-1
>> redundancy guarentee unless a drive fails.
>
> So (assuming 1GB chunksize):
>
> if i create a raid-1, btrfs with a 3GB and a 7GB device, it will show=
me ~10GB free space,
> after saving a 1GB file, i will have 8GB left (-1GB on each device)
> after saving another 1GB, i will have 6GB left (--- " ----)
> after saving another 1GB, it's "suddenly" full?
you have still 4GB free of non RAID-1 (single) space, which is
currently unavailable, but it is planned that BTRFS will support mixed
storage:
some files can be RAID-1, some files can be RAID-0 and rest is basic
(single) storage
>
> Fabian--
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next prev parent reply other threads:[~2012-01-05 13:35 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-05 9:21 Why does Btrfs allow raid1 with mismatched drives? Also: How to look behind the curtain Fabian Zeindl
2012-01-05 9:43 ` Fabian Zeindl
2012-01-05 9:44 ` Hugo Mills
2012-01-05 9:53 ` Fabian Zeindl
2012-01-05 10:39 ` Martin Steigerwald
2012-01-05 12:26 ` Fabian Zeindl
2012-01-05 13:01 ` Martin Steigerwald
2012-01-05 13:35 ` Roman Kapusta [this message]
2012-01-05 13:47 ` Fabian Zeindl
2012-01-05 14:40 ` Martin Steigerwald
-- strict thread matches above, loose matches on Subject: below --
2012-01-05 14:41 Martin Steigerwald
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