Single service comparison

Persistent Disk is managed at a project scope and spans multiple disk families (zonal, regional, hyperdisk) that decouple performance from capacity in some types, while Huawei EVS service boundaries are simpler: it is the single block-storage service for ECS and BMS with four disk types (Extreme SSD, Ultra-high I/O, General Purpose SSD, General Purpose SSD V2). EVS disks are zone-scoped and attach within a single AZ; there is no first-party regional disk mirroring an AZ failure the way GCP regional PD does. For cross-zone resilience you must combine EVS with CBR backups, or rely on application-level replication.

The data and control models differ. GCP exposes disks via the Compute Engine API with consistent resource names, labels, and IAM-based, fine-grained access; EVS is exposed through the Huawei ECS/EVS APIs and IAM policies scoped to the Huawei account and region, with attachment limited to ECS/BMS in the same AZ. EVS offers up to 32 TiB per disk and up to 16-server shared-disk attachment via SCSI-3 PR, comparable to GCP multi-writer, but EVS shared-disk concurrency semantics and queue depth tuning differ and must be validated per workload. EVS durability is delivered by three-copy redundancy within the AZ.

Integration and operational responsibility diverge. GCP Persistent Disk integrates natively with images, snapshots, and the Backup and DR Service, and disk performance is observability-driven through Cloud Monitoring. EVS integrates with CBR for backups and snapshots, Cloud Eye and Cloud Trace for monitoring and audit, and with KMS for encryption, but quota, region availability, and disk-type support vary by region and must be checked per target AZ. Architects retain responsibility for capacity planning, snapshot scheduling, and validation that EVS performance tiers match the source PD (GPs) baseline before cutover.

Assess the source PD inventory: disk type, size, IOPS/throughput baselines, snapshot cadence, encryption mode (CMEK vs default), and whether disks are zonal, regional, or hyperdisk. Map each disk to a Huawei EVS disk type by performance tier: Extreme SSD or Ultra-high I/O for high-IOPS database workloads, General Purpose SSD V2 for tunable IOPS, General Purpose SSD for cost-effective systems. Confirm target-AZ availability of the chosen disk type, the 32 TiB per-disk ceiling, and the shared-disk (16-server) limit where replication-style clusters are in use. There is no native PD-to-EVS one-click path; design a recomposed stack with EVS plus CBR for backups.

For data migration, transfer logical volumes rather than expecting block-level equivalence. Use application-level export/import, file-based copy (rsync, OSS transfer), or restore from GCP snapshots into image/object intermediates and rehydrate onto freshly created EVS disks attached to ECS. Recreate encryption by relating GCP CMEK keys to Huawei KMS grants, and rebuild snapshot schedules as CBR backup policies. Where GCP regional PD provided cross-AZ failover, compensate with CBR restore-to-new-AZ or application-level replication rather than assuming EVS regional mirroring exists.

Validate before cutover: run the workload read/write path against the new EVS disks and confirm IOPS, latency, and throughput meet the PD baseline measured in assessment. Exercise a CBR restore drill to confirm RTO/RPO, verify shared-disk quorum behaviour for clustered applications (Oracle RAC, WSFC), and confirm partition style (GPT for disks over 2 TiB, MBR only below). EVS partitions must be initialized manually when a disk is created empty or attached separately from ECS creation, mirroring a step that GCP handles implicitly via image-backed disks.

Account for cost-model and quota shifts. GCP bills PD by GB-month capacity plus snapshot storage and image usage, with some types decoupling IOPS from capacity; Huawei bills EVS capacity (GiB-month by disk type), snapshot backup storage under CBR, and request/transfer traffic. Recalculate TCO using peak IOPS configuration cost for General Purpose SSD V2, retention period for CBR backups, and inter-AZ or cross-region restore traffic. Validate EVS and CBR quotas per region before production cutover, since defaults may be lower than the corresponding GCP project quotas.