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Zorluk: OrtaBusiness Continuity and Disaster Recovery

A network engineering team is executing a disaster recovery failover plan to restore operations at a secondary data center following a catastrophic failure at the primary site. Arrange the recovery actions in the correct sequential order based on standard network and infrastructure service dependencies, from first to last.

  1. 1Establish foundational layer 2 switching and layer 3 routing infrastructure at the disaster recovery site.
  2. 2Restore core infrastructure and directory services, including Active Directory, internal DNS, and DHCP.
  3. 3Recover backend database storage volumes and line-of-business application servers from backups.
  4. 4Perform validation and synthetic testing to verify data integrity and service functionality.
  5. 5Update external DNS records and edge gateway routing to cut over client traffic to the secondary site.

Cevap

The correct order of steps is: 1) Establish foundational layer 2 switching and layer 3 routing infrastructure, 2) Restore core infrastructure and directory services (Active Directory, internal DNS, DHCP), 3) Recover backend database storage volumes and application servers, 4) Perform validation and synthetic testing to verify data integrity, and 5) Update external DNS records and edge gateway routing to cut over client traffic.
Disaster recovery failovers must adhere strictly to infrastructure dependency order. Underlying network switching and routing must be restored first to enable inter-subnet communication. Next, core directory and name resolution services (Active Directory, DNS, DHCP) must be brought online so that subsequent hosts can resolve IP endpoints and authenticate. Once directory services exist, application and database servers can be restored and booted. Comprehensive validation testing is conducted prior to production exposure. Finally, external DNS records and edge routing are updated to direct live client traffic to the recovered site.

Adım Adım Çözüm

1
Identify physical and network layer prerequisites.
Switching, VLAN trunking, and inter-VLAN routing at the DR site are brought online.
Without active layer 2 and layer 3 networking, host machines cannot perform network communication or reach backup repositories.
2
Identify core network service dependencies.
Domain controllers, DNS servers, and DHCP relays are restored.
Enterprise applications rely on domain authentication and hostname resolution during startup scripts and database connection strings.
3
Restore data and application servers.
Database volumes and application virtual machines are recovered from backups.
With directory services online, application workloads can connect to databases and register domain security SIDs.
4
Verify operational readiness.
Synthetic end-to-end tests are executed internally by network and system admins.
Exposing production users to unvalidated systems risks data corruption or service outages.
5
Divert live client traffic.
Public DNS A/AAAA/CNAME records and BGP/edge routes are modified.
Traffic cutover must be the final action after confirming all underlying dependencies are operating as expected.

Anahtar Kavram

Disaster Recovery Infrastructure Dependency Sequence
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