Backup fails due to GRPC error (gitlab 12.10.14)

Dear All,

we have a 12.10.14 GitLab CE on CentOS 7 installation and in the last days, backup is failing with the message (it does not happen with the same repository):

gitlab-rake gitlab:backup:create SKIP=registry,artifacts

Gitlab::Git::CommandError: 4:Deadline Exceeded

Caused by:
GRPC::DeadlineExceeded: 4:Deadline Exceeded

does anyone know the reason (tried with --trace but unable to understand)?

I paste the output messages down here;

thank you
regards
Stefano

Gitlab::Git::CommandError: 4:Deadline Exceeded
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/git/wraps_gitaly_errors.rb:13:in rescue in wrapped_gitaly_errors' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/git/wraps_gitaly_errors.rb:6:in wrapped_gitaly_errors’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/git/repository.rb:1039:in uncached_has_local_branches?' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/git/repository.rb:167:in block in has_local_branches?’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/utils/strong_memoize.rb:30:in strong_memoize' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/git/repository.rb:166:in has_local_branches?’
/opt/gitlab/embedded/service/gitlab-rails/app/models/repository.rb:553:in has_visible_content?' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache_adapter.rb:84:in block (2 levels) in cache_method_asymmetrically’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache.rb:44:in fetch_without_caching_false' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache_adapter.rb:179:in block (2 levels) in cache_method_output_asymmetrically’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/null_request_store.rb:34:in fetch' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/safe_request_store.rb:12:in fetch’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache.rb:25:in fetch' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache_adapter.rb:178:in block in cache_method_output_asymmetrically’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/utils/strong_memoize.rb:30:in strong_memoize' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache_adapter.rb:192:in block in memoize_method_output’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache_adapter.rb:201:in no_repository_fallback' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache_adapter.rb:191:in memoize_method_output’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache_adapter.rb:177:in cache_method_output_asymmetrically' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache_adapter.rb:83:in block in cache_method_asymmetrically’
/opt/gitlab/embedded/service/gitlab-rails/app/models/repository.rb:527:in empty?' /opt/gitlab/embedded/service/gitlab-rails/app/models/repository.rb:353:in expire_emptiness_caches’
/opt/gitlab/embedded/service/gitlab-rails/lib/backup/repository.rb:155:in empty_repo?' /opt/gitlab/embedded/service/gitlab-rails/lib/backup/repository.rb:25:in block in dump’
/opt/gitlab/embedded/service/gitlab-rails/lib/backup/repository.rb:16:in dump' /opt/gitlab/embedded/service/gitlab-rails/lib/tasks/gitlab/backup.rake:99:in block (4 levels) in <top (required)>’
/opt/gitlab/embedded/service/gitlab-rails/lib/tasks/gitlab/backup.rake:11:in block (3 levels) in <top (required)>' /opt/gitlab/embedded/bin/bundle:23:in load’
/opt/gitlab/embedded/bin/bundle:23:in `’

Caused by:
GRPC::DeadlineExceeded: 4:Deadline Exceeded
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/gitaly_client.rb:192:in execute' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/gitaly_client.rb:170:in block in call’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/gitaly_client.rb:198:in measure_timings' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/gitaly_client.rb:169:in call’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/gitaly_client/repository_service.rb:99:in has_local_branches?' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/git/repository.rb:1040:in block in uncached_has_local_branches?’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/git/wraps_gitaly_errors.rb:7:in wrapped_gitaly_errors' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/git/repository.rb:1039:in uncached_has_local_branches?’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/git/repository.rb:167:in block in has_local_branches?' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/utils/strong_memoize.rb:30:in strong_memoize’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/git/repository.rb:166:in has_local_branches?' /opt/gitlab/embedded/service/gitlab-rails/app/models/repository.rb:553:in has_visible_content?’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache_adapter.rb:84:in block (2 levels) in cache_method_asymmetrically' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache.rb:44:in fetch_without_caching_false’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache_adapter.rb:179:in block (2 levels) in cache_method_output_asymmetrically' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/null_request_store.rb:34:in fetch’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/safe_request_store.rb:12:in fetch' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache.rb:25:in fetch’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache_adapter.rb:178:in block in cache_method_output_asymmetrically' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/utils/strong_memoize.rb:30:in strong_memoize’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache_adapter.rb:192:in block in memoize_method_output' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache_adapter.rb:201:in no_repository_fallback’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache_adapter.rb:191:in memoize_method_output' /opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache_adapter.rb:177:in cache_method_output_asymmetrically’
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/repository_cache_adapter.rb:83:in block in cache_method_asymmetrically' /opt/gitlab/embedded/service/gitlab-rails/app/models/repository.rb:527:in empty?’
/opt/gitlab/embedded/service/gitlab-rails/app/models/repository.rb:353:in expire_emptiness_caches' /opt/gitlab/embedded/service/gitlab-rails/lib/backup/repository.rb:155:in empty_repo?’
/opt/gitlab/embedded/service/gitlab-rails/lib/backup/repository.rb:25:in block in dump' /opt/gitlab/embedded/service/gitlab-rails/lib/backup/repository.rb:16:in dump’
/opt/gitlab/embedded/service/gitlab-rails/lib/tasks/gitlab/backup.rake:99:in block (4 levels) in <top (required)>' /opt/gitlab/embedded/service/gitlab-rails/lib/tasks/gitlab/backup.rake:11:in block (3 levels) in <top (required)>’
/opt/gitlab/embedded/bin/bundle:23:in load' /opt/gitlab/embedded/bin/bundle:23:in
Tasks: TOP => gitlab:backup:repo:create