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OCI 1Z0-1123-25 Cheat Sheet

March 28, 2026

OCI 1Z0-1123-25 cheat sheet for key facts, traps, service mappings, and final review.

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Use this for last-mile review. Keep it open during mixed OCI migration questions and pair it with the Resources when you want Oracle’s exact migration wording.

1Z0-1123-25 usually gets easier when you classify the stem in this order:

  1. Phase lane: assessment, landing-zone prep, transfer, validation, cutover, or stabilization?
  2. Connectivity lane: VPN, FastConnect, DRG design, DNS, or hybrid path dependency?
  3. Cutover lane: online vs offline, outage tolerance, rollback trigger, and ownership?
  4. Readiness lane: data validation, application behavior, security, observability, and support coverage?

OCI answer sequence

Use this when the stem mixes ingress, async delivery, reliability, security, or operations.

    flowchart TD
	  S["Scenario"] --> I["Classify the interaction mode"]
	  I --> E["Pick API Gateway, Events, Notifications, Streaming, or Functions"]
	  E --> R["Check retry, idempotency, ordering, and dead-letter behavior"]
	  R --> S2["Check Vault, IAM, private exposure, logs, and auditability"]

Fast lane picker

If the question is mainly about… Start with… Usual winning move
where the migration is failing phase ordering assess, prepare, transfer, validate, cut over
connectivity path VPN vs FastConnect vs DRG hub choose by scale and predictability
downtime or risk online vs offline cutover choose by tolerated outage
proving readiness validation plan and rollback trigger cutover without validation is weak
hidden migration risk dependencies and operational visibility do not look only at the data copy step
landing zone quality IAM, network, compartments, DNS, observability prepare the target before moving workloads
tool choice workload shape, database type, transfer window, and sync needs tool fit beats tool popularity

Read every migration scenario in this order

  1. Decide whether the problem is discovery, landing-zone preparation, data movement, application migration, validation, cutover, or stabilization.
  2. Identify the source of truth for data, DNS, identity, and monitoring at each stage.
  3. Match the connectivity method to bandwidth, predictability, and timing needs.
  4. Separate replication or transfer from actual production cutover.
  5. Keep rollback ownership and business validation explicit.

Phase outputs

Phase What strong answers usually produce
assess workload inventory, dependencies, recovery needs, risk register
design landing zone, connectivity, IAM, DNS, security, observability plan
move data transfer and workload relocation path matched to outage tolerance
validate data checks, app smoke tests, access tests, alarms, logging, runbooks
cut over explicit switch step, owner, communication plan, rollback trigger
stabilize post-cutover review, issue monitoring, cleanup, decommission sequencing

Discovery and assessment reminders

Area What to capture
workloads app type, database type, statefulness, uptime needs
dependencies identity, DNS, certificates, integrations, third-party endpoints
performance baseline throughput, latency, peak windows, and storage profile
data profile size, change rate, sensitivity, retention, and validation method
operations owners, escalation, runbooks, monitoring, and maintenance windows
risk rollback constraints, business blackout dates, and compliance requirements

Migration phase map

    flowchart TD
	  Assess["Assess and Map Dependencies"] --> Design["Design Landing Zone and Connectivity"]
	  Design --> Move["Move Data and Workloads"]
	  Move --> Validate["Validate Data, Apps, Security, Observability"]
	  Validate --> Cutover["Cut Over"]
	  Cutover --> Stabilize["Stabilize and Review"]

Fast rule: strong migration answers separate preparation, transfer, validation, and cutover instead of compressing them into one generic “migrate” step.

Landing-zone checklist

Area What should be ready before workload move
IAM groups, policies, dynamic groups, service access
networking VCNs, subnets, routes, security rules, private connectivity
DNS public/private zone behavior and target records
security keys, secrets, certificates, logging, audit
observability logs, alarms, dashboards, alert routing
operations support ownership, ticketing, runbooks, rollback contacts

Connectivity chooser

Requirement Strongest first fit Why
faster setup and lower cost IPSec VPN simpler private path
higher bandwidth and steadier latency FastConnect stronger dedicated connectivity lane
many-network routing hub DRG-based design centralized path control
bulk transfer with predictable private path FastConnect plus well-planned routing reduces network surprise
early validation before full production movement VPN or staged connectivity where constraints permit proves dependency path sooner

Connectivity boundary table

Boundary What it really answers Do not confuse it with
VPN or FastConnect how traffic reaches OCI privately the migration tool itself
DRG routing hub and attachment logic a validation or security workflow
DNS name resolution after or during migration actual network path existence
security rules whether traffic is allowed how traffic is routed
migration service/tool how data or workloads move the network path itself

Connectivity traps

Trap Better reading
choosing FastConnect automatically because it sounds enterprise-grade choose by bandwidth, latency, and migration need
designing migration without path validation connectivity assumptions break cutovers
ignoring dependency traffic between systems migration impact is wider than one workload
validating only source-to-target path app-to-db, user-to-app, and service-to-service paths also matter
assuming DNS can wait until after cutover name resolution often determines whether the switch actually works

Migration-tool fit reminders

Requirement Stronger first instinct
large bulk file transfer transfer service/object storage staging path
ongoing database synchronization database replication or migration service with cutover support
simple image or server move migration tooling matched to compute shape and dependency profile
app modernization do not pretend replatforming is only a data-transfer task
minimal outage data move continuous sync plus controlled switchover

Tool-selection traps

Trap Better reading
choosing one tool for every workload database, file, VM, and app moves differ
focusing on data copy speed only cutover, validation, and rollback matter too
migration complete when bytes arrive app behavior, identity, networking, and observability still matter

Downtime and cutover chooser

Constraint Strongest first fit Why
downtime is acceptable and simplicity matters offline cutover fewer moving parts
downtime must be minimized online sync plus controlled switchover reduces outage exposure
rollback must stay simple preserve clear source-of-truth boundary and reversion trigger safer recovery
many connected systems move together staged cutover with dependency-aware sequencing avoids partial failure chaos
low-risk business switch explicit freeze, communication, validation checkpoint, and rollback timer operations control matters
complex dependency graph phased cutover with service order awareness reduces cascading failures

Cutover-readiness table

Before switch, confirm… Because the exam often hides the miss here
data is current enough for the chosen cutover mode stale sync breaks otherwise-correct switches
application dependencies are reachable app readiness is broader than data presence
IAM, secrets, and DNS point to the target design users and services fail if only data moved
observability is already live in the target blind cutovers are weak answers
rollback owner and trigger are explicit rollback must be intentional, not implied
support team knows the switch window ownership failure is still migration failure

Cutover traps

Trap Better reading
treating cutover as just a DNS update traffic switch, app readiness, and data state all matter
moving production without rollback conditions rollback criteria should be explicit before cutover
assuming replicated data means the app is ready application behavior and dependency validation still matter
shutting down the source too early source-of-truth and rollback decisions need clear timing
cutover without freeze/control step uncontrolled writes can break sync assumptions

Validation checklist

Area What correct answers usually include
data counts, checksums, spot checks, consistency review
application smoke tests and critical workflow checks
security IAM, network rules, and secret rotation validation
observability alarms, dashboards, and log routing in the target environment
operations ownership, communication, and support readiness
performance baseline comparison and critical path latency
business acceptance key user workflows and known high-value transactions

Dependency-driven validation

Dependency type What to validate
identity users, workloads, roles, and secret access still work
network routes, private paths, allow rules, and DNS behavior
application critical transaction paths and service-to-service flows
data row counts, checksums, freshness, and business-critical spot checks
operations dashboards, alerts, ticket routing, escalation, and runbooks

Data-sync and validation traps

Trap Better reading
row counts alone prove success counts, checksums, spot checks, and workflow tests all matter
target data is current enough because sync was “running” measure lag and freshness explicitly
replicated data equals successful migration target operations, permissions, and app behavior still need proof

Migration dependency traps

Trap Better reading
focusing only on data transfer tool choice identity, DNS, networking, secrets, and monitoring are dependencies too
validating only data counts app behavior and operational readiness matter as well
assuming rollback is obvious rollback needs a trigger, owner, and tested path
skipping decommission planning old environment cleanup should follow verified stabilization
no post-cutover monitoring window stabilization is a real phase, not a sentence at the end

Stabilization and cleanup

Area Stronger post-cutover action
issue watch elevated monitoring and clear owner on standby
rollback window keep source and recovery options until confidence threshold is met
cleanup retire unused paths, credentials, and temporary sync tooling deliberately
cost remove duplicate resources once stabilization is complete
documentation record what changed, what failed, and what needs follow-up

High-confusion pairs

Pair Keep this distinction clear
transfer phase vs cutover phase moving data or workload versus making production depend on the target
connectivity validation vs application validation network path exists versus business workflow actually works
online migration vs zero-risk migration reduced outage does not remove cutover risk
rollback plan vs backup existence recovery intention and ownership versus stored copy of data
DRG routing design vs migration sequencing path construction versus move order and switch timing
landing zone prep vs validation target readiness before movement versus proof after movement
stabilization vs decommission proving the new state works versus removing the old state safely

Decision order that usually wins

  1. Classify the issue as assessment, landing-zone prep, transfer, validation, cutover, or stabilization.
  2. Keep source-of-truth ownership explicit for data, DNS, identity, and monitoring.
  3. Choose connectivity and migration tooling by bandwidth, sync need, and outage tolerance.
  4. Treat cutover as a controlled business event, not just a technical action.
  5. Preserve rollback, validation evidence, and post-cutover monitoring until the target is truly stable.

Last 15-minute review

If you only keep one thing from each lane… Remember this
sequencing assess, prepare, move, validate, cut over, stabilize
connectivity choose the least disruptive path that still meets scale needs
cutover online vs offline depends on downtime tolerance
validation data, app, security, and observability all need checks
rollback define the trigger before production switch
landing zone target IAM, DNS, networking, and monitoring should exist before move
stabilization migration is not over when traffic first lands successfully

What strong 1Z0-1123-25 answers usually do

  • identify whether the issue is connectivity, transfer, validation, or cutover control
  • choose the least disruptive migration path that still meets downtime and scale constraints
  • separate transfer, validation, and cutover as distinct responsibilities
  • preserve rollback options and operational visibility throughout the move
  • prepare the landing zone before trusting any migration tooling
  • treat stabilization, cleanup, and decommissioning as planned operational work
Revised on Sunday, May 10, 2026
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