1Z0-997-26 High Availability And Disaster Recovery Practice Test 2 — 15 Questions

Question 1

An Oracle Cloud Infrastructure (OCI) architect is designing a high-availability web tier across multiple Availability Domains (ADs) within a single region. Which component should be used to distribute incoming client traffic evenly across web server instances residing in different ADs?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

An OCI Public Load Balancer configured with backend sets spanning multiple ADs.. An OCI Public Load Balancer can be configured with backend sets that include web server instances in multiple Availability Domains within a region, distributing traffic evenly and providing high availability. It operates at Layer 7 (HTTP/HTTPS) and supports health checks to route traffic only to healthy instances. This design ensures that if one AD fails, traffic is automatically routed to instances in other ADs, meeting the high-availability requirement.

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An OCI Dynamic Routing Gateway (DRG) configured with equal-cost multi-path routing.

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A Network Load Balancer restricted to a single Availability Domain subnet.

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A primary Local Peering Gateway (LPG) connected to multiple VCNs.

Question 2

You are planning the backup retention strategy for critical Oracle Base Database Service instances in OCI. You want to retain weekly backups for 12 months and daily backups for 30 days. Where are these automated backups stored by default?

Accepted Answer

In an Oracle-managed Object Storage bucket inaccessible to direct user manipulation.. Automated backups for Oracle Base Database Service in OCI are stored in an Oracle-managed Object Storage bucket that is not directly accessible to customers. This design ensures backup integrity, security, and lifecycle management without requiring user intervention. The retention policies (weekly for 12 months, daily for 30 days) are applied to these backups automatically.

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In an OCI File Storage Service (FSS) mount target.

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In a customer-managed Block Volume attached to the database compute instance.

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In local temporary NVMe drives on the database node.

Question 3

An application deployed across two OCI regions uses a DNS-based traffic management steering policy. A database failure occurs in the primary region, and the application must failover to the secondary region. What is the primary limitation of relying solely on DNS Traffic Management for disaster recovery failover?

Accepted Answer

Client-side caching and DNS TTL expiration delays can cause continued traffic routing to the failed region.. DNS-based traffic management only influences which endpoint a client resolves to; it cannot force clients to stop using an address they have already cached. When the primary region fails, clients and recursive resolvers that cached the old record continue sending traffic to the failed region until the TTL expires and they re-query, so failover is inherently delayed and not instantaneous.

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DNS steering policies cannot route traffic across different geographic regions.

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DNS records are permanently immutable once created in OCI.

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DNS routing requires public IP addresses to be configured on the database backends.

Question 4

Your organization has a strict Recovery Point Objective (RPO) of 5 minutes and Recovery Time Objective (RTO) of 15 minutes for a multi-tier application. The database tier uses Oracle Data Guard. During a test drill, you notice that redo transport lag spikes to 8 minutes. What is the most likely architectural bottleneck causing this issue?

Accepted Answer

Inadequate cross-region network bandwidth or high latency causing redo transport congestion.. A redo transport lag spike to 8 minutes most likely indicates a network bottleneck between the primary and standby regions. Data Guard redo transport depends on sufficient cross-region bandwidth and low latency; if bandwidth is constrained or latency is high, the standby cannot receive and apply redo fast enough, causing the lag to exceed the 5-minute RPO. This is an architectural issue, not a database or application configuration issue.

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Exceeded OCI Block Volume IOPS limits on the standby database's local NVMe scratchpad.

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Misconfigured OCI IAM policy allowing read-only access to database backups.

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Incorrect OCI Load Balancer SSL certificate configuration on the web tier.

Question 5

When designing high availability across multiple Availability Domains in an OCI region, how should database or application subnets be configured to ensure fault tolerance?

Accepted Answer

Create regional subnets so that instances can be placed across multiple Availability Domains.. Regional subnets in OCI are not scoped to a single availability domain, so instances launched in them can be placed in any AD within the region. This allows you to spread database and application instances across multiple ADs for fault tolerance while keeping them in the same subnet and VCN.

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Restrict all subnets to a single Availability Domain to prevent cross-AD latency.

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Disable security lists on subnets to allow uninterrupted cross-AD replication traffic.

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Attach all VNICs directly to the Dynamic Routing Gateway without using subnets.

Question 6

An architect is configuring an OCI Full Stack Disaster Recovery plan. The plan includes a step to run a custom script on an application server during a failover drill. Which OCI service executes this custom script?

Accepted Answer

OCI Functions or OCI Compute instance run-command actions orchestrated by Full Stack DR.. OCI Full Stack Disaster Recovery orchestrates failover and drill plans that can include user-defined custom scripts. These scripts are executed either as OCI Functions invocations or as Compute instance run-command actions, which Full Stack DR calls as plan steps to run arbitrary logic on application servers during a drill or failover.

Answer

Oracle Autonomous Linux Auto-Update Daemon

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OCI Resource Manager Terraform apply jobs exclusively

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OCI Streaming Service consumer groups

Question 7

An application running on OCI compute instances requires disaster recovery protection. You want to replicate boot volumes and block volumes to a secondary region. Which OCI Block Volume feature facilitates this?

Accepted Answer

Asynchronous cross-region block volume replication. OCI Block Volume supports asynchronous cross-region replication, which continuously replicates block volumes (and their boot volumes) from a primary region to a secondary region for DR purposes. This is the native OCI feature designed for cross-region block volume DR. It operates at the block level and is configured per volume or volume group.

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OCI File Storage cross-mount replication policies

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Manual Object Storage export of raw volume blocks using dd commands

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Real-time synchronous block volume mirroring via software RAID

Question 8

You are configuring a Data Guard association between two Oracle Base Database Systems in different OCI regions. The primary database encounters an unplanned outage, and you perform a manual failover. What action must you take afterward if you wish to restore the original architecture with the old primary as the new standby?

Accepted Answer

Recreate or reinstate the former primary database (using Flashback Database or backup restoration) to convert it into a valid standby.. After a manual failover, the old primary is no longer a valid standby because its data files and control file reflect a different point in time. To restore the original architecture, you must reinstate or recreate the former primary as a standby, typically using Flashback Database to the point of the last redo it transmitted, or by restoring from backup and re-establishing the Data Guard association. Only then can redo transport resume in the reverse direction.

Answer

Run a simple 'SWITCHOVER' command to reverse roles without any data synchronization checks.

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Modify the listener.ora file manually via SSH and restart the clusterware.

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Delete the standby database and provision a brand-new VCN in the primary region.

Question 9

Which OCI service can be used to monitor the health and performance of your load balancers and backend compute instances across multiple availability domains, triggering alarms if health checks fail?

Accepted Answer

OCI Monitoring service with Alarm definitions. The OCI Monitoring service ingests metrics from load balancers, compute instances, and other resources, and lets you define alarms on those metrics that fire when thresholds (such as unhealthy backend count or health check failures) are breached. Alarms can trigger notifications via OCI Notifications and can drive autoscaling or Functions. This is the native OCI service for health and performance monitoring with alarm definitions.

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OCI DNS Traffic Management

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OCI Audit service

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OCI Vault service

Question 10

An architect is designing a multi-region disaster recovery architecture for an application running on OCI Compute. The database layer uses Oracle Data Guard. For the application tier, what is the recommended approach to handle stateless application servers in the DR region?

Accepted Answer

Pre-provision compute instances in a stopped state or use instance pools with standby configuration, activating them during a disaster event.. For stateless application servers in a DR region, the recommended OCI approach is to pre-provision capacity that can be activated quickly without paying for full-time compute. Instance pools with a standby configuration (or stopped instances) let you maintain a warm standby that can be scaled up or started during a failover event, meeting RTO while controlling cost. Because the app tier is stateless, no data synchronization is needed—only the ability to bring compute online and point it at the newly promoted database.

Answer

Run all application servers at full capacity in both regions simultaneously with active write locks.

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Store application binaries solely in Object Storage and compile them on the fly using user-data scripts during failover.

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Rely entirely on manual creation of compute instances via the OCI console after an outage occurs.

Question 11

Which OCI networking component is required to securely connect a VCN in one OCI region to a VCN in another OCI region for cross-region Data Guard database replication?

Accepted Answer

Dynamic Routing Gateway (DRG) with Remote VCN Peering. Remote VCN Peering in OCI uses a Dynamic Routing Gateway (DRG) attached to each VCN, with the two DRGs connected over OCI's private backbone to link VCNs in different regions. This provides private, encrypted-in-transit connectivity suitable for cross-region Data Guard redo transport without traversing the public internet. The DRG is the required routing anchor for any inter-VCN or on-premises connectivity in OCI.

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Internet Gateway (IGW)

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NAT Gateway

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Local Peering Gateway (LPG)

Question 12

You are performing maintenance on an OCI Load Balancer backend set. You want to temporarily stop sending traffic to a specific backend server without immediately dropping active persistent connections. What feature should you use?

Accepted Answer

Enable Connection Draining on the backend server.. Connection Draining is the OCI Load Balancer feature that gracefully removes a backend from rotation while allowing in-flight persistent connections to complete. When enabled, the backend is marked as draining, existing sessions continue until they finish or the drain timeout expires, and no new connections are routed to it. This matches the requirement to stop new traffic without abruptly dropping active persistent connections.

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Set the backend server weight to zero without enabling draining.

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Delete the backend server from the backend set immediately.

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Modify the security list to drop all TCP packets on port 443.

Question 13

Your organization has deployed an enterprise workload on OCI Exadata Database Service. You are configuring Data Guard with Fast-Start Failover (FSFO). To prevent split-brain scenarios where both primary and standby databases assume primary roles simultaneously, where must the Data Guard Observer be placed?

Accepted Answer

In a separate fault domain or external location independent of both the primary and standby database nodes.. The Data Guard Observer must run on a host that is independent of both the primary and standby database systems so it can act as an impartial third-party arbitrator during Fast-Start Failover. Placing it in a separate fault domain or external location ensures that a failure affecting either database node does not also take down the Observer, allowing it to reliably detect failures and issue the failover command without risking split-brain.

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Directly on the primary database compute node to ensure low-latency communication.

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Inside an OCI Object Storage bucket as a serverless function.

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Inside the same Oracle Grid Infrastructure clusterware home on the standby database.

Question 14

An architect is configuring Oracle Autonomous Database Disaster Recovery with cross-region Data Guard. The primary database is in Ashburn, and the standby is in Phoenix. You execute a switchover operation. What happens to the connection strings (such as tnsnames.ora entries) used by client applications?

Accepted Answer

Client connection strings remain valid; applications reconnect, and the regional endpoint automatically routes traffic to the new primary.. When using Oracle Autonomous Database with cross-region Data Guard, the connection strings (such as those in tnsnames.ora) remain valid after a switchover because the regional endpoint automatically routes traffic to the new primary database. Applications reconnect without any changes to their configuration. This is a key benefit of the managed service, which abstracts the underlying infrastructure changes.

Answer

The database IP addresses change, requiring manual DNS A-record updates in OCI DNS.

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You must manually regenerate new wallet zip files and redeploy them to all application servers.

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Client applications must be rewritten to use hardcoded IP addresses instead of TNS names.

Question 15

Which OCI storage service provides massively scalable, highly durable regional object storage that is ideal for storing database backups and disaster recovery artifacts?

Accepted Answer

OCI Object Storage. OCI Object Storage is a regional, internet-scale service designed for massive scalability and eleven-nines durability, making it the standard target for database backups, disaster recovery artifacts, and long-term retention. Its regional nature means data is redundantly stored across availability domains within a region, which is exactly what DR artifacts need.

Answer

OCI Block Volume

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Local NVMe Scratch Disks

Answer

OCI Boot Volumes