Il 2020-09-19 18:57 Pierre-Philipp Braun ha scritto:
On 19.09.2020 14:14, Gionatan Danti wrote:
cp --sparse=never
Hello neighbor (ciao from France).
I am not sure what you mean, as there **was both** the original and
the copied file sums in my message.
Sorry, I somewhat managed to miss them :|
Anyhow, thank you and good idea about --sparse=never. I applied the
checksum multiple times -- at at each step -- just to make sure the
results are consistent.
cp --sparse=never dummy.ext4 dummy-never.ext4
cp --sparse=auto dummy.ext4 dummy-auto.ext4
cp --sparse=always dummy.ext4 dummy-clone.ext4
And the sums always remain the same. So I only print the output only
once here below.
ce2b843692051a2f4f81366f9680b675 dummy.ext4
33e84fdf0a328a64c4edd00342dd433d dummy-never.ext4
33e84fdf0a328a64c4edd00342dd433d dummy-auto.ext4
33e84fdf0a328a64c4edd00342dd433d dummy-clone.ext4
Although the GFS2 sparse-file is fine and usable as-is, it cannot be
copied with `cp` nor packed with GNU tar, and it does not matter if
our aim is to actually keep the sparse.
I also attempted to copy a GFS2 sparse file to some EXT4 file-system.
cp --sparse=always dummy.ext4 /root/dummy-clone-on-ext4.ext4
And same happens.
33e84fdf0a328a64c4edd00342dd433d /root/dummy-clone-on-ext4.ext4
While with the inverse, namely copying an EXT4 sparse-file on GFS2.
cd /root/
dd if=/dev/zero of=dummy-on-ext4.ext4 bs=1G count=0 seek=1
mkfs.ext4 dummy-on-ext4.ext4
cp --sparse=always dummy-on-ext4.ext4 /data2/dummy-clone-from-ext4.ext4
delivers the sparse-file intact. No problem there.
cd573cfaace07e7949bc0c46028904ff /root/dummy-on-ext4.ext4
cd573cfaace07e7949bc0c46028904ff /data2/dummy-clone-from-ext4.ext4
and... WOW! Cloning it yet again, it finally remains intact!
cd573cfaace07e7949bc0c46028904ff dummy-clone-from-ext4-and-clone.ext4
cd573cfaace07e7949bc0c46028904ff dummy-clone-from-ext4.ext4
It's strange. Anyone?
Absolutely. Really strange.
In case it matters, I am using vanilla Linux 4.18.20 and not the RHEL
nor CentOS with patches.
What distribution are you using (Slackware)? Any additional data about
your filesystem (ie: num journals/nodes)? I would like to try to
replicate the issue if I can find some spare time...
Thanks.
--
Danti Gionatan
Supporto Tecnico
Assyoma S.r.l. - www.assyoma.it
email: g.danti@xxxxxxxxxx - info@xxxxxxxxxx
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