Hello,
I'm not sure this is the right forum to ask on but I'll try and if its
not I do apologize. I have also created a stack overflow question
without success (
https://stackoverflow.com/questions/54634703/btrfs-send-with-parent-different-size-depending-on-source-of-files
) but ill paste the question here too. Thank you.
What i'm trying to achieve is sending only the diff of the parent with
btrfs send -p
Running this will produce a file 'out' with size 639 bytes, i.e only
diff sent.
====================================================
btrfs subvolume create A
btrfs subvolume create B
mkdir A/dir
dd if=/dev/urandom of=A/dir/server.jar bs=1024 count=40K
cp --reflink=always A/dir/server.jar B/server.jar
btrfs subvolume snapshot -r A a
btrfs subvolume snapshot -r B b
btrfs send -p a b > out
====================================================
However if I change the dd command to wget like this:
====================================================
btrfs subvolume create A
btrfs subvolume create B
mkdir A/dir
wget -O A/dir/server.jar
https://launcher.mojang.com/v1/objects/20c069d373e77265aaeeedb733f7051e294325a3/server.jar
cp --reflink=always A/dir/server.jar B/server.jar
btrfs subvolume snapshot -r A a
btrfs subvolume snapshot -r B b
btrfs send -p a b > out
====================================================
The 'out' file is 34M, which is the full size.
What causes this?
