Disaster Recovery

GitLab (fewer requirements)
Minimum hardware requirements: 4 vCPU and 4 GB RAM support up to 500 users. No specific recommendation for disk size.
GitLab Geo (Premium) allows replication of a GitLab instance to other geographical locations as a read-only fully operational instance that can also be promoted in case of disaster.
Supporting up to 3000 users, requires 8 vCPUs, 48 GB RAM, 300 GB attached storage, 200 GB root storage.
GHES has a configuration, in which a fully redundant secondary GitHub Enterprise Server appliance is kept in sync with the primary appliance through replication of all major datastores. GitHub calls this configuration HA, but since the failover is manual, it's defined here as a DR.