Mirroring Steps

1. Create the mirror Target as an empty repository (e.g. at github.com as shown here):

1. In the Source repository at gitlab.common-lisp.net (e.g. cmucl/cmucl), enter the Settings -> Repository area:

1. Click the ">" to open the "Mirroring Repositories" item:

1. Click to "Add New" and fill out the "Git repository URL" according to the pattern shown:

1. Select "SSH public key" for Authentication Method, click "Detect Host Keys" button, and fill in "git" for the Username. Click the "Mirror repository" button:

1. Click the Clipboard icon next to your new Mirror item in the listing (tooltip: "Copy SSH public key"):

1. Under user profile Settings back in github (or other target repository host), add a new SSH key and paste the contents copied in (6) above:

1. Click the circle-arrows icon (tooltip: "Update Now") next to your new mirror and wait a while for the initial mirror to populate (watch for any red "Error" tag immediately thrown - if not, that's a good sign). Note the initial populating may take a while for a large repo:

Confirm the "Last successful update" shows recently as expected.

Your mirror should now be live!