snapshots (archive files) are too big ... Why?

[Houder]

On 2016-01-23 20:25, Corinna Vinschen wrote:
> On Jan 23 20:09, Houder wrote:
>> On 2016-01-23 19:10, Corinna Vinschen wrote:

>> >I found out why this happens, I just don't know why it only occurs since
>> >2015-07-20.
>> >
>> >The reason is the script is using an expression along the lines of
>> >
>> >  find ... | tar -T - --no-recursion -cjf ...
>> >
>> >It turns out that the --no-recursion option only works for me, if it
>> >comes *prior* to the expression specifying the filenames to archive.
>> >That is, I had to change the script to use
>> >
>> >  find ... | tar --no-recursion -T - -cjf ...
>> >
>> >instead.  Funny enough, `info tar' still contains an example using
>> >the original order...
>> 
>> Ah, thank you for the effort you took and for your explanation. (yes,
>> the reason for the "big" files was simpler than I was guessing at).
>> 
>> However, I cannot confirm your finding at my end (using Cygwin). 
>> Still,
>> I am sure you will take another look at the size of a snapshot when 
>> you
>> create one the next time :-)
> 
> Of course I created local test snapshots using the above change.  They
> only have one version of each file and are considerably smaller than 
> the
> previous versions.  I'm building on Fedora Linux if that matters.

@@ mkdir x
@@ cd x
@@ tar xJf ../cygwin-inst-20160121.tar.xz
@@ find etc usr | wc -l
381

# preferred order (options)? tar manual: 6.9 Descending into 
Directories)
@@ find etc usr | tar --no-recursion -T- -cJf ../foo.tar.xz

# NOT the preferred order (options)?
@@ find etc usr | tar -T- --no-recursion -cJf ../foo2.tar.xz
@@ tar tvJf ../foo.tar.xz > foo1
@@ tar tvJf ../foo2.tar.xz > foo2
@@ diff foo1 foo2
@@ wc -l foo*
   381 foo1
   381 foo2
   762 total
@@

Did the same test on FC19. Same result.

But, let it rest for the moment, I would advice. Next time when you will
build a snapshot, you (we) will know.

Regards,
Henri

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