Single service comparison

Service boundary and endpoint scope differ materially. DataSync covers file-to-file, file-to-object, and object-to-object paths, supporting NFS, SMB, S3 API, and several AWS-native destinations through agents deployed in the source environment or AWS-managed locations. OMS is narrower and purpose-built: it migrates object data from third-party cloud object stores and HTTP/HTTPS-accessible self-built object systems into Huawei OBS, and does not present a general file-system migration path. Architects should treat OMS as the object-only subset of DataSync's broader transfer surface, not a like-for-like replacement.

Control and data plane models differ. DataSync exposes tasks, locations, and agents via AWS APIs and integrates with EventBridge, CloudWatch, and IAM for scheduling, monitoring, and access control, with checksum and in-transit encryption over a managed network path. OMS offers wizard-based migration and synchronization tasks with prefix/list/time-based object selection, automatic task splitting, resumable transfer, HTTPS in transit, and optional KMS encryption at rest in OBS, plus SMN notifications. OMS lacks DataSync's agent deployment model and file-protocol support, which changes network egress, source-side setup, and operational responsibility.

Scaling, regional availability, and economics differ. DataSync scales throughput via task concurrency and agent sizing, with billing per GB transferred plus source egress and storage costs, across AWS Regions. OMS scales by splitting large tasks into concurrent groups and bills for migrated data volume and OBS request/storage usage, with egress determined by the source provider. OMS regional reach depends on Huawei Cloud OBS availability and supported source endpoints; architects must verify source compatibility, target region, and quotas per task rather than assuming global parity with DataSync.

Start with assessment before selecting a target. Inventory S3 buckets, object counts, total volume, storage classes, lifecycle rules, KMS encryption, object-lock retention, tags, and access policies. Map storage classes to OBS tiers (Standard, Infrequent Access, Archive) and confirm OMS supports the source endpoint and authentication method. OMS is the direct equivalent for object-to-OBS migration; file-system sources are out of scope and require a different service such as SMS or a custom pipeline, so do not assume one tool covers both.

Configure OMS migration or synchronization tasks for the data move. Use prefix, list, or time-based object selection to stage large datasets, enable automatic task splitting for concurrency, and set traffic limiting to constrain source egress. Preserve metadata where supported, enable HTTPS for in-transit encryption, and configure target OBS bucket encryption with KMS keys. For delta or ongoing sync before cutover, use OMS synchronization tasks rather than one-shot migration tasks, and plan retries for failed objects from the recorded migration log.

Validate integrity and prepare cutover. After OMS completes, compare object counts, sizes, and ETags/hashes between source and OBS, verify lifecycle, replication, and bucket policies, and run application read tests against OBS endpoints. Schedule cutover during a maintenance window, switch application write paths to OBS, and run a final OMS synchronization pass to capture late writes. Keep the source bucket read-only during cutover to avoid divergence, and retain it until validation completes.

Address capability gaps and cost-model changes. OMS does not replicate DataSync's file-to-object or NFS/SMB transfer paths, so file workloads need SMS, a self-managed pipeline, or re-architecture to OBS. Recalculate TCO using OMS migrated-data charges, OBS storage tier GB-month, request operations, KMS usage, retrieval/restore, and source-provider egress, modeling peak load, object count, and retention period. Confirm target-region OBS availability, encryption key residency, and any per-task quotas, and route governance through MgC for migration orchestration where a composed pattern is needed.