Yeap, looks like the exact same issue.

Answering your questions from the bug conversation:
1. # guix-daemon —version
guix-daemon (GNU Guix) 0.9.0
2. # df /tmp
Filesystem	1K-blocks	Used	Available	Use%	Mounted on
unionfs		2854060		830856	2023204	30%		/

On /mnt/tmp it should be ext4 because I formatted whole partition after creation (mkfs.ext4).

Thanks.

Best regards,
dptd

> On 21 Mar 2016, at 10:23, Ludovic Courtès <ludo@gnu.org> wrote:
> 
> dptdescribe <dptdescribe@gmail.com> skribis:
> 
>> tests/store.scm
>> guix system: error: build failed: build of `/gnu/store/…db1-guix-0.9.0.71e2065.drv’ failed
> 
> This looks like what’s reported at <http://bugs.gnu.org/23056>.
> 
> Could you answer the questions I asked there?  :-)
> 
> Thanks,
> Ludo’.