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Re: qcow2 preallocation and backing files
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From: |
Alberto Garcia |
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Subject: |
Re: qcow2 preallocation and backing files |
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Date: |
Wed, 20 Nov 2019 16:18:27 +0100 |
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User-agent: |
Notmuch/0.18.2 (http://notmuchmail.org) Emacs/24.4.1 (i586-pc-linux-gnu) |
On Wed 20 Nov 2019 01:27:53 PM CET, Vladimir Semeeausntsov-Ogievskiy wrote:
> 3. Also, the latter way is inconsistent with discard. Discarded
> regions returns zeroes, not clusters from backing. I think discard and
> truncate should behave in the same safe zero way.
But then PREALLOC_MODE_OFF implies that the L2 metadata should be
preallocated (all clusters should be QCOW2_CLUSTER_ZERO_PLAIN), at least
when there is a backing file.
Or maybe we just forbid PREALLOC_MODE_OFF during resize if there is a
backing file ?
Berto