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Re: [Qemu-discuss] qcow2 performance improve
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From: |
Alberto Garcia |
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Subject: |
Re: [Qemu-discuss] qcow2 performance improve |
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Date: |
Thu, 16 Aug 2018 13:07:40 +0200 |
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User-agent: |
Notmuch/0.18.2 (http://notmuchmail.org) Emacs/24.4.1 (i586-pc-linux-gnu) |
On Thu 16 Aug 2018 10:20:12 AM CEST, address@hidden wrote:
>>If there is no backing file or snapshot you still need to fill the
>>cluster with zeroes, and that's going to be slower with larger
>>clusters.
>
> If not fill zeroes and only write guest data ,what`s wrong could
> happen ?
The following could happen:
1) Guest reads at offset [0, 4k] -> there's only zeroes
2) Guest writes at offset [8k, 16k]
3) Guest reads at offset [0, 4k] -> there's something else now
Berto