Add backups runbook

This is an old branch and probably out of sync.

Can you pick it up and update it?

howto/backups.md

+# Backups and restore
+We currenty have multiple backup solutions:
+- AWS snapshots by `ebs.gitlap.com`
+- Azure snapshots by `azure.gitlap.com`
+- GitLab backup for database and pages
+
+## AWS snapshots
+### Snapshots
+Every night on `ebs.gitlap.com` the following snapshot script `/opt/gitlab-backup/bin/gitlab-ebs-snapshot` creates snapshots for all EC2 instances.
+### Restore
+https://dev.gitlab.org/cookbooks/gitlab-backup/blob/master/doc/gitlab-ebs-snapshot.md#restoring
+
+## Azure snapshots
+### Snapshots
+Every night on `azure.gitlap.com` the following snapshot script `/opt/gitlab-backup/bin/gitlab-azure-snapshots` creates snapshots for the Azure instances mentioned in `/etc/gitlab-azure-snapshots.yml`.
+
+Just add the chef role `"role[azure-snapshot]"` to a node and snapshots will be created.
+
+### Restore
+On `azure.gitlap.com` you can use script `/opt/gitlab-backup/bin/gitlab-azure-restore` to restore the snapshots and attach the data disks to a new created instance.
+
+So to restore i.e. file-storage1.cluster.gitlab.com follow these steps:
+#### Create new node
+```
+~/chef-repo/tools/bin/azure-create-node --role backend file-storage2.cluster.gitlab.com
+```
+#### Restore snapshot and attach the data disks
+Login into `azure.gitlap.com`
+
+You can get a list of available epochs by checking the snapshot info files in /var/lib/gitlab-azure-snapshots:
+```
+ls -al /var/lib/gitlab-azure-snapshots/
+```
+Restore snapshots:
+```
+/opt/gitlab-backup/bin/gitlab-azure-restore --epoch 1463965202 --source file-storage1.cluster.gitlab.com file-storage2.cluster.gitlab.com
+```
+
+#### Activate logical volume
+Activate the logical volume in the new created node:
+```
+# LVM support
+sudo apt-get install -y lvm2
+# look for gitlab_vg on the attached drives
+sudo vgchange -ay gitlab_vg
+# make sure the mountpoint exists
+sudo mkdir -p /var/opt/gitlab
+# mount the logical volume at /var/opt/gitlab
+sudo mount /dev/gitlab_vg/gitlab_com /var/opt/gitlab
+```