Hello Liu
On 03/28/2012 04:18 AM, Liu Bo wrote:
On 03/28/2012 06:24 AM, Matthias G. Eckermann wrote:
# time cp -a --reflink /var/lib/lxc/installserver_tmp/rootfs /var/lib/lxc/installserver
This is too much weird.
AFAIK, clone between different subvolumes should be forbidden.
So this would get a "Invalid cross-device link", because an individual subvolume can be mounted directly.
Could you elaborate which would be the issue ?
"cp --reflink"-ing a file is not different than snapshotting a file. In
any case I could mount a snapshot and not the source subvolume.
thanks,
liubo
real 0m1.367s
user 0m0.148s
sys 0m1.108s
## Now remove /var/lib/lxc/installserver_tmp (or not)
------------------------------< snap>------------------------------
Just to compare this with a "mv":
------------------------------< snip>------------------------------
## Go back to former state
# btrfs subvol delete /var/lib/lxc/installserver
Delete subvolume '/var/lib/lxc/installserver'
# btrfs subvol create /var/lib/lxc/installserver
Create subvolume '/var/lib/lxc/installserver'
# time mv /var/lib/lxc/installserver_tmp/rootfs /var/lib/lxc/installserver/
real 0m12.917s
user 0m0.208s
sys 0m2.508s
------------------------------< snap>------------------------------
While the time measurement might be flawed due to the subvol
actions inbetween, caching etc.: I tried several times, and
"cp --reflinks" always is multiple times faster than "mv" in
my environment.
Or did I misunderstand your question?
so long -
MgE
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