Pass the Huawei HCS-Pre-sales H19-308_V4.0 Questions and answers with Dumpstech

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.

Unlike traditional file storage which uses a hierarchical tree structure, Huawei Object Storage utilizes a flat structure where each "object" is a self-contained unit of data. According to the documentation, an object consists of four fundamental components:

Data (Option D):The actual content of the file (e.g., a photo, video, or document).

System Metadata (Option C):These are fixed attributes managed by the storage system, such as file size, creation date, last modified time, and HTTP content type.

Customized Metadata (Option B):A unique advantage of object storage is the ability to attach user-defined tags or labels to an object (e.g., "Patient_ID: 12345" or "Department: Radiology"). This allows for advanced data indexing and searching without opening the file itself.

Object Identifier (OID) (Option A):This is the unique key or "Address" used to retrieve the object. In a flat namespace, the OID ensures that every piece of data can be located instantly without traversing a complex directory path.

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).

Unlike traditional storage architectures that use an Asymmetric Logical Unit Access (ALUA) model where a LUN is "owned" by a primary controller, Huawei OceanStor Dorado utilizes a Symmetric Active-Active architecture. In this design, LUNs do not have a specific owner. Instead, all controllers in a cluster can simultaneously receive and process I/O requests for the same LUN.

This is made possible by theSmartMatrix full-mesh interconnect, which allows any interface module to communicate with any controller, and any controller to access any disk. Because there is no concept of "LUN ownership," there is no need for time-consuming "LUN handovers" if a controller fails. This symmetry eliminates performance bottlenecks, ensures balanced load distribution across all hardware resources, and provides a smoother experience for host-side multipathing software. This architectural shift is a key differentiator for the Dorado series, enabling it to deliver consistent, high-speed performance even during controller maintenance or failure.

In Huawei OceanStor storage systems utilizing RAID 2.0+ and the SmartMatrix architecture, the "write penalty" associated with traditional RAID is mitigated through Full-Stripe Writes. In a partial write (where only some data in a stripe is updated), a RAID 5 setup usually suffers a write penalty of 4 (Reading old data, reading old parity, writing new data, writing new parity).

However, Huawei's controllers utilize a large cache to aggregate incoming data. When enough data is collected to fill an entire stripe (e.g., 8 data chunks plus 1 parity chunk in an 8+1 RAID 5 setup), the system performs aFull-Stripe Write. In this scenario, the system calculates the parity in the CPU/cache and writes the entire stripe to the disks at once. Since no old data or old parity needs to be read from the physical disks before writing, the disk-levelwrite penalty is 0. This significantly enhances the write performance of hybrid arrays, especially those using mechanical HDDs which are highly sensitive to the latency of extra read/write operations.

According to Huawei’s storage networking guides, Fibre Channel (FC) supports three primary physical topologies to facilitate communication between servers (initiators) and storage arrays (targets).

Point-to-point (Option C):This is the simplest topology where two nodes are directly connected. It provides dedicated bandwidth but lacks scalability.

Arbitrated loop (FC-AL) (Option D):In this setup, devices are connected in a loop shared by all nodes. While more scalable than point-to-point, only one pair of nodes can communicate at a time, leading to performance bottlenecks as more devices are added.

Fabric (FC-SW) (Option A):This is the most common enterprise topology, utilizing FC switches. It allows many-to-many communication, providing high scalability, redundancy, and independent bandwidth for each connection.

"Bus" (Option B) is a topology associated with older Ethernet or SCSI standards and is not a recognized topology in Fibre Channel networking. Huawei OceanStor Dorado and Hybrid systems primarily utilize theFabric topologyfor large-scale data center deployments to ensure maximum availability and performance through redundant switch fabrics.

Huawei documentation highlights several key advantages of object storage for modern data requirements. Option A is correct because object storage primarily uses RESTful APIs (HTTP/HTTPS), which are firewall-friendly and accessible globally over the internet, unlike NFS/CIFS/SMB which are generally restricted to local area networks (LANs).

Option B is correctbecause object storage allows forextensible metadata. Users can attach custom tags to objects, enabling powerful data searching and automated lifecycle management without needing an external database to track file attributes.Option D is correctbecause object storage uses aflat namespacerather than the tree-shaped directory structure of NAS. In a flat structure, adding more nodes to the system does not increase the complexity of data retrieval, allowing for nearly infinite horizontal scalability. Option C is incorrect in this context because the tree-shaped directory is actually a limitation of NAS that causes performance degradation at high scales, whereas object storage avoids this hierarchy to improve expansion capabilities.

The Huawei OceanStor Dorado series is engineered for 99.9999% availability using multiple layers of reliability. Option A is correct as RAID-TP (Triple Parity) is a unique Huawei feature that uses three parity chunks to tolerate the simultaneous failure of any three SSDs in a disk group. Furthermore, the SmartMatrix full-mesh architecture in high-end models allows the system to remain operational even if seven out of eight controllers in a controller enclosure fail, ensuring extreme service continuity.

Option B is correctbecause Huawei utilizesGlobal Wear Levelingto distribute writes across all SSDs to extend their lifespan, andAnti-Wear Levelingto prevent multiple SSDs from reaching their end-of-life simultaneously, which avoids multi-disk failure risks.Option C is correctas the system supportsHyperMetro(Active-Active) for both block (SAN) and file (NAS) services, providing zero RTO and RPO across sites.Option D is correctbecause Dorado supports high-reliability disk enclosure connection technologies; in a multi-enclosure setup, the system can tolerate the failure of an entire disk enclosure without data loss by using intelligent data distribution across different enclosures.

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 aligns with the market analysis provided in Huawei’s OceanStor Pacific pre-sales documentation regarding the "Yottabyte Era". Huawei highlights that the nature of data is shifting away from structured databases toward massive volumes of unstructured data, such as high-definition video, medical images, IoT sensor logs, and AI training datasets.

By 2025, it is projected that80% of new data generatedwill be unstructured. This trend is the primary driver behind the development of the OceanStor Pacific series, which is ascale-out distributed storagesystem specifically designed to handle the capacity and performance requirements of unstructured data at scale. Traditional centralized arrays (SAN/NAS) are often ill-equipped to handle the sheer volume and file counts associated with this growth, necessitating the move toward distributed architectures that can scale horizontally to hundreds of petabytes.