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Re: Backup problem using "cp"




On May 7, 2018 4:31:16 AM PDT, Richard Owlett <rowlett@xxxxxxxxxxx> wrote:
>On 05/06/2018 10:11 AM, Thomas Schmitt wrote:
>> Hi,
>> 
>> Richard Owlett wrote:
>>> Thought I was doing that by specifying -x.
>> 
>> Either cp -x has a bug or the target directory is not in a different
>> filesystem than "/" and not a mount point of such a filesystem.
>> 
>> Check the device numbers of "/" and "/media/richard/MISC...".
>> E.g. like this
>> 
>>    $ stat / | fgrep Device
>>    Device: 803h/2051d      Inode: 2           Links: 25
>>    $ stat /bkp | fgrep Device
>>    Device: 814h/2068d      Inode: 2           Links: 7
>> 
>> Here "/bkp" has a different device number (2068) than "/" (2051).
>> So it (its inode, to be exacting) is in a different filesystem.
>> 
>> As contrast see a directory in the same filesystem as "/":
>> 
>>    $ stat /home | fgrep Device
>>    Device: 803h/2051d      Inode: 2228225     Links: 60
>
>I get:
>richard@debian-jan13:~$ stat / | fgrep Device
>Device: 80eh/2062d	Inode: 2           Links: 22
>richard@debian-jan13:~$ stat /media | fgrep Device
>Device: 80eh/2062d	Inode: 131073      Links: 5
>richard@debian-jan13:~$
>
>I gather that "cp" is then an inappropriate tool.
>
>"tar" is inappropriate for my preferences - I was attempting to use
>"cp" 
>as there would be multiple files &/or directories as input *and*
>output.
>
>I suspect long term I want "rsync" [ *MUCH* reading to do! ]


You will indeed want rsync.  Essentially, "rsync -av [--delete] <source> <destination> will serve most of your backup needs.
-- 
David Griffith
dave@xxxxxxx