shinya

It's basically maintenance-free, and if you got trouble, you can ask in Issue Tracker https://gitlab.com/gitlab-org/gitlab-ce/issues. We can advise how you can recover your instance case-by-case. (Also, there is a feature for backup your local data to cloud storage https://docs.gitlab.com/ee/raketasks/backup_restore.html. This is useful in case your machine'HDD died suddenly)

To troubleshoot your problem smoothly, I'd advise not to modify your GitLab instance intentionally, for instance, applying own custom patch, changing database schema, etc.

> - IF YOU USE THE BUILT IN CACHE, parallelism will be hard (you cannot populate part of the cache from a job, another part from another job and in the next step use the result of both cache)

You can use the `artifacts` and `dependencies` combo to leverage which artifact will be downloaded into a particular job.

For instance,

    bundle-install:
    stage: build
    script: ...
    artifacts:
        paths: [bin/*]

    yarn-install:
    stage: build
    script: ...
    artifacts:
        paths: [bin/*]

    rspec:
    stage: test
    script: ...
    dependencies: [bundle-install] # This downloads only `bundle-install` artifact to this job

    karma:
    stage: test
    script: ...
    dependencies: [yarn-install] # This downloads only `yarn-install` artifact to this job

    eslint:
    stage: test
    script: ...
    dependencies: [] # This downloads nothing

https://docs.gitlab.com/ee/ci/yaml/#dependencies explains how it works