Re: How to delete system generations?

[huang ying <huang.ying.caritas@gmail.com>]

Hi, Ludo,

Thanks for help!

On Mon, Jan 9, 2017 at 4:50 AM, Ludovic Courtès <ludo@gnu.org> wrote:
> Hello,
>
> huang ying <huang.ying.caritas@gmail.com> skribis:
>
>> For package, there is
>>
>> $ guix package --delete-generations
>>
>> But, for system, I don't find similar stuff?  Is there something for that?
>
> Not yet!  But you can run:
>
>   sudo rm /var/guix/profiles/system-123-link
>
> to delete generation 123.  Be careful to choose the right number!

Great to know that.  It is quite simple.

>> I need that because I found the contents of the following store item is invalid,
>>
>> /gnu/store/s9mrff47jfp9b3bhgv59q2kzwbmi6rl8-fatfsck-static-4.0
>>
>> $ ls -l /gnu/store/s9mrff47jfp9b3bhgv59q2kzwbmi6rl8-fatfsck-static-4.0/sbin
>> total 0
>> -r-xr-xr-x 1 root root 0 Jan  1  1970 fsck.fat
>> lrwxrwxrwx 4 root root 8 Jan  1  1970 fsck.vfat -> fsck.fat
>
> How do you know it’s invalid?

The size of fsck.fat is 0.

Then I done some experiment to change the package via adding some
(display "") and the newly generated fatfsck-static has fsck.fat file
with non-zero size.

>> I want to regenerate it and the initrd.  But I don't know how.  One
>> way is to delete all generations depends on it, gc it, then regenerate
>> it.  But I don't know how to delete system generations.
>>
>> Or is there some other way to work around this?
>
> When the store is corrupt, you can run ‘guix gc --verify=contents,repair’:
>
>   https://www.gnu.org/software/guix/manual/html_node/Invoking-guix-gc.html
>
> That will check the integrity of each item in /gnu/store (thus it’s very
> I/O-intensive and can take a lot of time) and, if it finds a corrupt
> item, will try to fetch a substitute to replace it.  That’s really a
> last resort, though.

Good to know this.  I will try to gc the system, so package and initrd
firstly.  That should be cheaper.

Best Regards,
Huang, Ying