What are *.xz compressed kernel modules for (Fedora 21)

[Kevin Wilson]

Hi,

I have Fedora 21 (x86_64).
Under /usr/lib/modules/3.17.4-302.fc21.x86_64/kernel, all the kernel
module are in compressed form.
(xz files).
Under
 /usr/lib/modules/3.17.4-302.fc21.x86_64/kernel, the kernel modules
are in the *.ko form

What are the *.xz compressed kernel modules for ? In fedora 20 we had
only *.ko files under /lib/modules.

It seems to me that after booting, when running modprobe, only the
*.ko modules are used.

Just wonder what would happen If I would (accidentally or by purpose)
delete the /lib/modules folder in fedora 21 (I don't intend to do it
before getting an answer here...)

Regards,
Kevin

[poma]

On 02.02.2015 20:34, Kevin Wilson wrote:
> Hi,
>
> I have Fedora 21 (x86_64).
> Under /usr/lib/modules/3.17.4-302.fc21.x86_64/kernel, all the kernel
> module are in compressed form.
> (xz files).
> Under
>  /usr/lib/modules/3.17.4-302.fc21.x86_64/kernel, the kernel modules
> are in the *.ko form
>
> What are the *.xz compressed kernel modules for ? In fedora 20 we had
> only *.ko files under /lib/modules.

kernel.spec: xz compress modules on i686 and x86_64
http://pkgs.fedoraproject.org/cgit/kernel.git/commit/?id=8922622
https://lists.fedoraproject.org/pipermail/kernel/2014-May/005253.html

[Stephen Morris]

On 02/03/2015 06:34 AM, Kevin Wilson wrote:
> Hi,
>
> I have Fedora 21 (x86_64).
> Under /usr/lib/modules/3.17.4-302.fc21.x86_64/kernel, all the kernel
> module are in compressed form.
> (xz files).
> Under
>   /usr/lib/modules/3.17.4-302.fc21.x86_64/kernel, the kernel modules
> are in the *.ko form
>
> What are the *.xz compressed kernel modules for ? In fedora 20 we had
> only *.ko files under /lib/modules.
>
> It seems to me that after booting, when running modprobe, only the
> *.ko modules are used.
>
> Just wonder what would happen If I would (accidentally or by purpose)
> delete the /lib/modules folder in fedora 21 (I don't intend to do it
> before getting an answer here...)

I would not delete /lib/modules otherwise the kernel would fail I suspect.
/lib is not a physical directory as such, /lib is a point to /usr/lib, 
so when you do a ls /lib/modules what you are listing is actually 
/usr/lib/modules.
> Regards,
> Kevin