[libvirt] Bump tar format?

[Michal Privoznik]

On 13.06.2016 11:46, Andrea Bolognani wrote:
> On Mon, 2016-06-13 at 09:57 +0100, Daniel P. Berrange wrote:
>>> Since RHEL5 support has been dropped for a while now, maybe it's time to
>>> revisit changing the tar format
>>
>> Yep, IIUC we should be fine for require pax support for the vintage of
>> Linux we required.  *BSD should be fine too, so IIUC, their tar version
>> uses libarchive which supports pax.  Windows has 7-zip which can do pax
>> and of course cygwin. Finally OS-X has the pax command and support in
>> the apple archive utility.
>>
>> So I think we're be fine to require it.
>>
>> While, we're changing this, I think we should probably take the opportunity
>> to also switch over to using 'xz' as our compression format, instead of gz.
>> Consider the 1.3.5 release compressed with different formats:
>>
>>  35109092  libvirt-1.3.5.tar.gz
>>  25573966  libvirt-1.3.5.tar.bz2
>>  12112612  libvirt-1.3.5.tar.xz
>>
>> Those results seem pretty compelling to me :-)
> 
> xz compression sure takes a lot of time!

Maybe it does, but it's done just once, while decompression is done
multiple times. So I think we can switch to xz. In fact, I'd be okay
with nothing but xz.

But will this solve the issue? I mean, the problem that Cole is seeing
(and I'm too) with too long path names. Isn't tar the origin of it?
Because if it is, I fear that changing compression algorithm won't help
much.

Michal