Backup is greating 22 bytes zip file only

Hello I am using docker version 0.13.0+dev on raspberry pi 4 aarch64 Manjaro linux.
What I am doing is:

$ docker exec -it mg_gogs_server bash

and then:

5b2edece61f7:~$ cd /backup/
5b2edece61f7:/backup$ /app/gogs/gogs backup
2021/01/30 18:24:07 [ INFO] Backup root directory: /tmp/gogs-backup-764575509
2021/01/30 18:24:07 [ INFO] Packing backup files to: gogs-backup-20210130182407.zip
2021/01/30 18:24:07 [ INFO] Dumping repositories in "/data/git/gogs-repositories"
2021/01/30 18:39:16 [ INFO] Repositories dumped to: /tmp/gogs-backup-764575509/repositories.zip

the problem the zip file is 22 bytes only and I have dozens of repository.
Can anyone suggest me something?

ah, I now see the /tmp//gogs-backup-764575509 contains big file;

5b2edece61f7:/backup$ ls -la /tmp/gogs-backup-764575509
total 2525972
drwx------    3 git      git           4096 Jan 30 18:24 .
drwxrwxrwt    1 root     root          4096 Jan 30 18:39 ..
drwxr-xr-x    2 git      git           4096 Jan 30 18:24 db
-rw-r--r--    1 git      git            114 Jan 30 18:24 metadata.ini
-rw-r--r--    1 git      git      2586571591 Jan 30 18:39 repositories.zip

why it is not in zip?

5b2edece61f7:/backup$ df 
Filesystem           1K-blocks      Used Available Use% Mounted on
overlay               61129128   7335100  51276448  13% /
tmpfs                    65536         0     65536   0% /dev
tmpfs                  4007528         0   4007528   0% /sys/fs/cgroup
shm                      65536         0     65536   0% /dev/shm
/dev/md127           2884023328 2026185912 711314344  74% /data
/dev/md127           2884023328 2026185912 711314344  74% /backup
/dev/mmcblk0p2        61129128   7335100  51276448  13% /etc/resolv.conf
/dev/mmcblk0p2        61129128   7335100  51276448  13% /etc/hostname
/dev/mmcblk0p2        61129128   7335100  51276448  13% /etc/hosts
tmpfs                  4007528         0   4007528   0% /proc/asound
tmpfs                    65536         0     65536   0% /proc/keys
tmpfs                    65536         0     65536   0% /proc/latency_stats
tmpfs                    65536         0     65536   0% /proc/timer_list
tmpfs                    65536         0     65536   0% /proc/sched_debug
tmpfs                  4007528         0   4007528   0% /sys/firmware

/data and /backup are host filesystems

Sorry, I have just re-run and waited for one hour and it created the zip file correctly. It is 2.4GB
However this is not what I was looking for. I am looking for an export of all git repositories. I mean an export similar to git clone and I do not want to have bare format.
Any hint?