* Why is "btrfs send" large after "cp --reflink"?
@ 2020-12-22 13:23 Torsten Bronger
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From: Torsten Bronger @ 2020-12-22 13:23 UTC (permalink / raw)
To: linux-btrfs
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Hallöchen!
1. I have a subvolume "VirtualBox" with an OS image (50 GiB VDI file).
2. I create a read-only snapshot with "btrfs su sn -r VirtualBox
parent".
3. I work with the OS, changing some data within the VDI file.
4. "btrfs p s VirtualBox ro true"
5. "btrfs send -p parent VirtualBox | wc -c" yields 60 MiB.
6. "btrfs su c temp"
7. "cp -a --reflink VirtualBox/* temp"
(takes less than 1 sec)
8. "btrfs send -p parent temp | wc -c" yields 12 GiB.
Why does "cp --reflink" break so much that the size of "btrfs send"
jumps from almost nothing to one quarter of the whole subvolume
size?
Regards,
Torsten.
--
Torsten Bronger
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2020-12-22 13:23 Why is "btrfs send" large after "cp --reflink"? Torsten Bronger
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