H19-308_V4.0 HCSA-Presales-Storage V4.0 Questions and Answers

Huawei OceanStor Dorado utilizes RAID 2.0+ block virtualization technology, which supports Dynamic RAID Reconstruction. In a traditional RAID environment, if a disk fails, the RAID group continues to operate in a "degraded" mode until the disk is replaced. However, in Dorado's RAID 2.0+, the system uses a distributed spare space policy where spare capacity is spread across all disks in the pool.

When one SSD fails in a storage pool originally configured with RAID 6 (7 data chunks + 2 parity chunks), the system identifies that it no longer has enough physical disks to maintain a 7+2 stripe width. To maintain the same level of protection (dual parity) while utilizing the remaining 8 disks, the system dynamically adjusts the RAID policy for new writes and reconstructed data toRAID 6 (6+2). This ensures that the data remains protected by two parity chunks even with a reduced disk count. This "shrinkage" of the stripe width allows the system to remain in a "healthy" protected state rather than staying in "degraded" mode indefinitely.

Huawei OceanStor Dorado high-end models (such as the 18000 series) utilize the SmartMatrix 4.0 architecture to provide industry-leading resilience. Option A is correct because these models can tolerate the failure of an entire controller enclosure (containing 4 controllers) without interrupting services, as the other enclosure in the cluster continues to handle all I/O. Option B is correct because Dorado features a Symmetric Active-Active design where any LUN is not owned by a specific controller; instead, any controller in the cluster can directly access any LUN, eliminating the performance bottleneck caused by traditional ALUA (Asymmetric Logical Unit Access) and ensuring load balancing.

Option C is correctas Huawei employsSmart Disk Enclosuresequipped with their own CPU and memory. These enclosures can offload tasks like data reconstruction (RAID rebuilds) from the main controllers, significantly speeding up recovery times and reducing the performance impact on host I/O during a disk failure.Option D is incorrectbecause OceanStor Dorado is anAll-Flasharray; it does not support HDDs and therefore does not perform tiering between flash and mechanical media (which is a function of the OceanStor Hybrid Flash series).

Huawei’s HyperReplication technology is designed to provide robust data redundancy across geographically separated storage systems. According to official technical specifications, Huawei storage supports two primary replication modes:

Synchronous Remote Replication (Option A):In this mode, data is written to both the local and remote storage systems simultaneously. The host receives a write-completion acknowledgement only after the data is successfully stored in both locations. This ensures zero data loss (RPO = 0) but is sensitive to network latency and is typically limited to distances within 100km to 300km.

Asynchronous Remote Replication (Option C):Data is first written to the local storage, and the host receives an immediate acknowledgement. The data is then synchronized to the remote site at defined intervals or based on specific triggers. This mode is not limited by distance and has minimal impact on application performance, though it carries a risk of minor data loss (RPO > 0).

Terms like "Semi-synchronous" or "Semi-asynchronous" (Options B and D) are not standard replication modes in the Huawei OceanStor architectural framework.

According to Huawei’s technical documentation on storage media, Solid State Drives (SSDs) fundamentally differ from Hard Disk Drives (HDDs) in their physical construction and data access methods. HDDs rely on mechanical components, including rotating platters and moving read/write heads. This mechanical nature introduces "rotational latency" and "seek time," which inherently limit the number of Input/Output Operations Per Second (IOPS).

In contrast, Huawei’s OceanStor SSDs utilize flash memory chips (NAND Flash) and a high-performance controller. Because there are no moving parts, the "seek time" is eliminated, allowing for near-instantaneous data access. This results in significantly higher random IOPS and much lower latency (often measured in microseconds rather than milliseconds). Furthermore, Huawei’sFlashLink® technologyfurther optimizes the collaboration between the storage controller and the SSDs, ensuring that even as the drive fills up, the performance remains consistent and the latency remains low. Therefore, in any performance-oriented storage environment, SSDs are the preferred choice over traditional HDDs.

Huawei’s object storage solution (OceanStor Pacific/OBS) is designed for massive scalability and high availability across geographic boundaries. Option C is correct because the Global Namespace feature abstracts the physical location of data, allowing users to access objects via a single URL/endpoint regardless of which Data Center or Availability Zone (AZ) the data physically resides in. This simplifies application development and data management at scale.

Options A and B are correctas the architecture supports multi-regional deployment. Data can be replicated between regions to ensure disaster recovery and data sovereignty. Unlike traditional SAN/NAS replication which is often limited by latency-sensitive synchronous protocols, object storage utilizes asynchronous transfer mechanisms optimized for the HTTP/S3 protocol. This leads toOption D being correct; because object storage replication is typically asynchronous and handles high latency well, sites can be separated by thousands of kilometers, making it an ideal solution for global data distribution and remote site backup.

To meet the customer's requirement for departmental isolation and resource control, Huawei recommends the combination of Multi-tenancy (Option C) and Quotas (Option D).12

Multi-tenancyis the foundational feature for iso3lation in Huawei object storage. It allows the physical storage system to be logically partitioned into multip4le "Tenants". Each department can be assigned its own tenant environment with its own set of users, access keys, and buckets. Data is logically isolated, meaning one department cannot see or access the data of another unless explicitly permitted.

Quotamanagement is then used to limit the capacity consumed by each department. In Huawei OceanStor Pacific, quotas can be applied at the Tenant level or the Bucket level. By setting a Tenant Quota, the administrator ensures that a specific department does not exceed its allocated budget of storage space, preventing one department from exhausting the resources of the entire system. While Replication (Option A) and WORM (Option B) are valuable for data protection, they do not address the specific needs of departmental isolation and capacity limiting.

Huawei OceanStor BCManager (Business Continuity Manager) is the dedicated software suite designed for managing disaster recovery and backup environments. While other tools perform different functions, BCManager is specifically engineered to orchestrate the entire DR lifecycle:

Management (eReplication):This component manages disaster recovery for various applications (like databases and VMs). It automates the recovery process, performs DR drills without interrupting services, and visualizes the DR topology.

Backup (eBackup):This component handles the backup of virtualized environments.

In contrast,DeviceManager (Option B)is the on-box management tool for single-array configuration.SystemReporter (Option A)is used for performance analysis and reporting.eService (Option D)is a cloud-based proactive monitoring and maintenance platform. Therefore, BCManager is the correct choice for specialized DR management.

This statement is false because Huawei's new-generation OceanStor hybrid flash storage features a converged (Unified) architecture that supports Native NAS capabilities directly within the storage controllers. In older storage generations or with competitors, an external "NAS Gateway" or "Filer" was often required to provide file services on top of block storage.

Huawei’sHyperMetro for NASis a gateway-free active-active solution. The file systems are managed natively by the storage OS (OceanStor OS), allowing both SAN and NAS services to benefit from the same high-availability features. By eliminating the need for an external gateway, Huawei simplifies the network topology, reduces hardware costs (TCO), and minimizes latency by removing an extra processing hop for file data. This native integration allows for seamless cross-site active-active deployments for file protocols like CIFS/SMB and NFS, just as it does for block protocols.

In the Huawei OceanStor RAID 2.0+ architecture, Redundant Array of Independent Disks (RAID) levels are used to balance performance, capacity, and reliability. RAID 0, also known as "striping," distributes data blocks across multiple physical disks to maximize I/O performance. By allowing multiple disks to be read or written simultaneously, it provides the highest throughput and capacity utilization (100%).

However, the defining characteristic of RAID 0 is the complete lack of redundancy. Unlike RAID 1 (Mirroring), RAID 5 (Parity), or RAID 6 (Dual Parity), RAID 0 does not store redundant information or parity bits. Huawei documentation explicitly states that if any single physical disk in a RAID 0 group fails, the entire RAID group becomes inaccessible, and all data within that group is lost. Therefore, RAID 0 is strictly recommended only for temporary data or scenarios where data loss is acceptable and maximum performance is the sole priority. For enterprise production environments, Huawei recommends RAID 5, RAID 6, or RAID-TP.

This statement reflects the architectural evolution of Huawei OceanStor systems. The Small Computer System Interface (SCSI) protocol was designed decades ago for mechanical drives (HDDs). It uses a single command queue with a depth of 32 commands, which was sufficient for the physical limitations of rotating platters and moving heads.

In contrast,Non-Volatile Memory express (NVMe)was designed specifically for flash media. It replaces the legacy SCSI stack to eliminate bottlenecks. NVMe supports up to 64,000 queues, each with 64,000 commands, allowing for massive parallelism. Huawei OceanStor Dorado (All-Flash) systems utilizeEnd-to-End NVMe(from the SSD to the controller, and from the controller to the host via NVMe-oF) to achieve microsecond-level latency. While modern flash arrays can still use SCSI (via FC or iSCSI) for compatibility, the full performance potential of an all-flash array is only realized through NVMe. Therefore, in modern storage design, SCSI is the legacy standard for HDDs/Hybrid arrays, while NVMe is the optimized standard for All-Flash arrays.

This statement accurately reflects the technical characteristics of traditional incremental backup strategies found in Huawei data protection guides. An Incremental Backup only copies the data that has changed since the last backup (whether that was a full or an incremental backup).

While this saves significant time and storage space during thebackup window, it adds complexity duringrestoration. To fully restore a system to its latest state, the administrator must first restore the lastFull Backupand then sequentially apply every subsequentIncremental Backupin the correct order. If any single incremental tape or file in the chain is missing or corrupted, the restoration cannot be completed beyond that point. Because the system must process multiple data sets to reconstruct the final image, the total recovery time (RTO) is indeed longer and the process is slower compared to restoring from a single Full Backup.

Huawei’s HyperLock feature provides WORM (Write Once, Read Many) functionality for NAS file systems. When a file is placed in the WORM state, the storage system strictly enforces a policy where the file's data can be accessed and read by authorized users, but any attempt to modify, overwrite, or delete the file is blocked by the storage controller.

In the Huawei OceanStor system, a file enters the WORM state after it is "locked." Once locked, the file remains in a read-only state for a defined retention period. During this time, not even an administrator can modify the file's content or reduce its protection duration. This is critical for meeting regulatory compliance (such as SEC Rule 17a-4) and for protecting sensitive data against ransomware, as it ensures that once data is archived, it remains immutable and verifiable. Only after the retention period has expired can the file be deleted, though it can still never be modified.

This statement is false because RAID 0 and Mirroring (RAID 1) are fundamentally different concepts in Huawei storage technology. As defined in the Huawei technical manual, RAID 0 is "Striping." It breaks data into chunks and spreads them across multiple disks to increase performance. It has no redundancy.

"Mirroring" is the terminology specifically used for RAID 1. In a RAID 1 configuration, the system writes the exact same data to two separate physical disks simultaneously. This creates a 100% redundant copy (a mirror). If one disk fails, the other continues to provide data, ensuring zero downtime and no data loss. Huawei'sRAID 2.0+ virtualization technologycan implement striping and mirroring across different "chunks" or "extents" within a storage pool, but it maintains the technical distinction: RAID 0 is for performance through striping, while mirroring is for reliability through duplication. Therefore, characterizing RAID 0 as a mirroring technology is a technical inaccuracy.

Huawei’s Multi-protocol Lossless Interworking is a standout feature of the OceanStor Pacific series, allowing one copy of data to be shared across different protocols (File, Object, HDFS).

No Semantic or Performance Compromise (Option B):Historically, protocol conversion (e.g., using a gateway) led to performance loss or "semantic loss" where certain file attributes or object tags were dropped. OceanStor Pacific implements native support for multiple protocols at the metadata level, ensuring full semantic compatibility and high-speed access regardless of the protocol used.

Zero Data Copy (Option C):This feature allows one piece of data to be written via one protocol (e.g., ingested via S3) and read via another (e.g., analyzed via HDFS) without moving or copying the data to a separate system. This eliminates "data silos" and greatly improves data processing efficiency.

Gateway-free (Option D):Because the interworking is native to the storage OS, no external protocol gateways are required. This simplifies the management architecture and reduces the hardware footprint.

Option A is incorrectbecause documentation generally advises against mixing structured (Database) and unstructured data in the same pool for optimal performance, though the system is primarily optimized for unstructured workloads.

Huawei OceanStor Pacific is a distributed scale-out storage system optimized for mass unstructured data (File, Object, HDFS). While it provides robust "always-on" service capabilities, Option A is incorrect as it refers to a specific feature of centralized unified storage arrays like the OceanStor Dorado series. OceanStor Dorado is marketed as providing the industry's only "Active-active solution for SAN and NAS" within a centralized architecture.

In contrast, OceanStor Pacific ensures service continuity through distributed mechanisms:

Fast Failover (Option B):Technologies such as multi-module concurrent service takeover enable services on a faulty node to be taken over within 10 seconds, minimizing RTO.

HyperGeoMetro (Option C):This feature provides multi-replica cross-site active-active protection for object storage, allowing data to be accessed and modified at multiple sites simultaneously.

HyperGeoEC (Option D): This is a cross-site Erasure Coding (EC) multi-active solution that provides high reliability and space utilization for large-scale deployments.

Because OceanStor Pacific is designed for distributed unstructured workloads rather than integrated SAN/NAS block-and-file convergence in the traditional sense, Option A is the outlier.