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Difficulty: Very hardBusiness Continuity and Disaster Recovery

An enterprise network storage system suffered a catastrophic volume failure on Thursday at 14:15. The network administrator maintains a disaster recovery plan with the following backup schedule:

- Full Backup: Executed every Sunday at 00:00
- Differential Backup: Executed daily Monday through Wednesday at 23:00
- Incremental Backup: Executed hourly on Thursday between 01:00 and 14:00
- Transaction Log Backup: Executed every 15 minutes

To restore the system to the point of failure in the shortest total downtime while maintaining complete data integrity, in what order should the network administrator execute the restoration steps?

  1. 1Restore the Sunday 00:00 full backup to the initialized target storage array.
  2. 2Restore the Wednesday 23:00 differential backup.
  3. 3Apply Thursday's hourly incremental backups sequentially from 01:00 through 14:00.
  4. 4Apply the 14:15 transaction log backup.
  5. 5Execute filesystem consistency checks and restore client network access.

Answer

The correct restoration sequence is: 1) Restore the Sunday 00:00 full backup, 2) Restore the Wednesday 23:00 differential backup, 3) Apply Thursday's hourly incremental backups sequentially from 01:00 through 14:00, 4) Apply the 14:15 transaction log backup, and 5) Execute filesystem consistency checks and restore client network access.
Optimal recovery requires restoring the full backup baseline first (Sunday 00:00). Next, restoring the latest differential backup (Wednesday 23:00) brings the volume current through Wednesday night in a single step, bypassing the redundant Monday and Tuesday differentials. All incremental backups taken on Thursday (01:00 through 14:00) must then be applied sequentially because each incremental relies on the state of the preceding backup. Applying the 14:15 transaction log backup recovers remaining transactions to achieve zero data loss. Finally, running consistency checks before opening client connections validates system health.

Step-by-Step Solution

1
Restore the initial baseline image.
The target array is populated with the Sunday 00:00 full backup.
All recovery processes require a full backup as the primary foundation image.
2
Apply the latest cumulative differential backup.
The Wednesday 23:00 differential backup is restored over the baseline.
Differential backups record all changes since the last full backup. Applying Wednesday's differential restores all data changes from Monday, Tuesday, and Wednesday in a single operation.
3
Apply subsequent delta changes chronologically.
Thursday's hourly incremental backups (01:00 through 14:00) are restored in strict sequential order.
Incremental backups capture changes made only since the preceding backup. Because the Wednesday differential reset the cumulative marker, all Thursday incrementals must be applied in order.
4
Replay point-in-time transaction logs.
The 14:15 transaction log backup is applied to bridge the gap between 14:00 and 14:15.
Transaction log replays bring database and file metadata to the precise moment before crash, minimizing RPO.
5
Verify storage volume integrity and reconnect network shares.
Volume consistency checks pass and production services are re-enabled.
System verification ensures data consistency and prevents exposing corrupt file handles to network clients.

Key Concept

Disaster recovery backup restoration sequencing combining full, differential, incremental, and transaction log backups.
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Topics

Business Continuity and Disaster Recovery

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