Merge branch 'docs/troubleshooting-git' into 'master'

Add new “Troubleshooting Git” page to General documentation

See merge request gitlab-org/gitlab-ce!15903

doc/topics/git/index.md

@@ -61,6 +61,10 @@ We've gathered some resources to help you to get the best from Git with GitLab.
   - [Getting Started with Git LFS](https://about.gitlab.com/2017/01/30/getting-started-with-git-lfs-tutorial/)
   - [Towards a production quality open source Git LFS server](https://about.gitlab.com/2015/08/13/towards-a-production-quality-open-source-git-lfs-server/)
 
+## Troubleshooting
+
+- Learn a few [Git troubleshooting](troubleshooting_git.md) techniques to help you out.
+
 ## General information
 
 - **Articles:**

doc/topics/git/troubleshooting_git.md

+# Troubleshooting Git
+
+Sometimes things don't work the way they should or as you might expect when
+you're using Git. Here are some tips on troubleshooting and resolving issues
+with Git.
+
+## Broken pipe errors on git push
+
+'Broken pipe' errors can occur when attempting to push to a remote repository.
+When pushing you will usually see:
+
+```
+Write failed: Broken pipe
+fatal: The remote end hung up unexpectedly
+```
+
+To fix this issue, here are some possible solutions.
+
+### Increase the POST buffer size in Git
+
+**If pushing over HTTP**, you can try increasing the POST buffer size in Git's
+configuration. Open a terminal and enter:
+
+```sh
+git config http.postBuffer 52428800
+```
+
+The value is specified in bytes, so in the above case the buffer size has been
+set to 50MB. The default is 1MB.
+
+### Check your SSH configuration
+
+**If pushing over SSH**, first check your SSH configuration as 'Broken pipe'
+errors can sometimes be caused by underlying issues with SSH (such as
+authentication). Make sure that SSH is correctly configured by following the
+instructions in the [SSH troubleshooting] docs.
+
+There's another option where you can prevent session timeouts by configuring
+SSH 'keep alive' either on the client or on the server (if you are a GitLab
+admin and have access to the server).
+
+NOTE: **Note:** configuring *both* the client and the server is unnecessary.
+
+**To configure SSH on the client side**:
+
+-  On UNIX, edit `~/.ssh/config` (create the file if it doesn’t exist) and
+   add or edit:
+
+    ```
+    Host your-gitlab-instance-url.com
+      ServerAliveInterval 60
+      ServerAliveCountMax 5
+    ```
+
+- On Windows, if you are using PuTTY, go to your session properties, then
+  navigate to "Connection" and under "Sending of null packets to keep
+  session active", set "Seconds between keepalives (0 to turn off)" to `60`.
+
+**To configure SSH on the server side**, edit `/etc/ssh/sshd_config` and add:
+
+```
+ClientAliveInterval 60
+ClientAliveCountMax 5
+```
+
+### Running a git repack
+
+**If 'pack-objects' type errors are also being displayed**, you can try to
+run a `git repack` before attempting to push to the remote repository again:
+
+```sh
+git repack
+git push
+```
+
+### Upgrade your Git client
+
+In case you're running an older version of Git (< 2.9), consider upgrading
+to >= 2.9 (see [Broken pipe when pushing to Git repository][Broken-Pipe]).
+
+[SSH troubleshooting]: ../../ssh/README.md#troubleshooting "SSH Troubleshooting"
+[Broken-Pipe]: https://stackoverflow.com/questions/19120120/broken-pipe-when-pushing-to-git-repository/36971469#36971469 "StackOverflow: 'Broken pipe when pushing to Git repository'"