Dual Boot Drives with RAID 1: Ensuring Operating System Redundancy in Bare Metal Servers

Why Dual Boot Drives Matter in High Availability

The boot drive houses the operating system, configuration files, and essential services that the server relies on to initialize and function. In a single-drive configuration, a simple disk failure can leave the server completely inaccessible, requiring manual intervention, remote reinstallation, or emergency disk replacement to restore service. This type of single point of failure is unacceptable in high availability designs, especially for platforms running critical infrastructure like OpenStack control planes or Ceph cluster nodes.

By using two dedicated boot drives in a RAID 1 mirror, OpenMetal ensures that the operating system is continuously protected from disk-level failures. With RAID 1, every write to the primary boot drive is simultaneously mirrored to the secondary boot drive. This creates two identical copies of the OS at all times.

Automatic Failover at the Drive Level

If one of the boot drives experiences a failure — whether due to media degradation, controller errors, or other hardware issues — the RAID controller or software RAID stack immediately marks the failed drive as degraded and seamlessly directs all read and write operations to the surviving healthy drive. This failover occurs in real-time, without requiring manual administrative action, and without interrupting running services.

This design allows the server to remain fully operational while OpenMetal’s monitoring systems detect the degraded state and automatically alert our operations team for proactive drive replacement. Because both drives contain identical copies of all boot data, no reconfiguration, reinstallation, or recovery from backup is required — simply replacing the faulty drive triggers an automatic RAID rebuild, bringing the mirror back into full redundancy.

Benefits Beyond Redundancy

The dual-boot-drive approach also supports best practices for lifecycle management. For example, if a firmware update or OS patching process causes unexpected instability, administrators can temporarily break the mirror, leaving one drive untouched as a rollback point while the updated system runs on the other. This capability adds flexibility when handling OS-level maintenance on production infrastructure. The RAID 1 setup is tested as part of our standard provisioning workflow to ensure it performs correctly in actual failure scenarios before any server is placed into production.

Redundancy from the Ground Up

By including RAID 1 mirrored boot drives as part of our standard HA server builds, OpenMetal ensures that even the most fundamental layer of the server’s software stack—the operating system itself—benefits from redundancy. This approach complements the higher-level redundancy mechanisms present in our architecture, such as:

• Dual power supplies for power fault tolerance.
• Dual uplinks to independent switches for network failover.
• Clustered service designs at the application layer to tolerate full server loss.

Together, these layers ensure that single hardware failures—whether a disk, power supply, or network port—never become service-impacting events.

OpenMetal Bare Metal Servers with Dual Boot Disks

OpenMetal’s v4 hardware catalog are all equipped with dual boot drives. The XL and XXL have 2x 960GB Boot Disks, while the Medium and Large have 2x 480GB Boot Disks.

OpenMetal’s use of dual RAID 1 boot drives reflects our broader commitment to resilient infrastructure design. Combined with our redundant networking, power, and clustering strategies, it ensures that the foundation of your infrastructure — the physical servers themselves — is as reliable as possible. Whether you’re running a Ceph storage node, an OpenStack control plane server, or any other critical service, OpenMetal’s boot drive redundancy helps safeguard your uptime from the ground up.