H19-308_V4.0 Practice Questions

A Storage Area Network (SAN) is a dedicated network for block-level data access. Huawei OceanStor systems support a variety of block-access protocols to ensure compatibility with different infrastructure environments. Fibre Channel (FC) is the industry standard for high-performance enterprise SANs, offering dedicated, low-latency, and lossless delivery. iSCSI provides block-level storage over standard TCP/IP Ethernet networks, making it a flexible and cost-effective alternative for many organizations.

InfiniBand (Option B)is a high-bandwidth, low-latency interconnect protocol often used in High-Performance Computing (HPC) and specialized SAN clusters to connect compute nodes to storage pools at extremely high speeds.NFS (Option D)is excluded from this answer because it is aNAS (Network Attached Storage)protocol. NFS (Network File System) provides file-level access rather than block-level access. While modern Huawei systems like the OceanStor Dorado series are "Unified Storage" (supporting both SAN and NAS on the same hardware), technically, only A, B, and C are considered SAN protocols.

Storage Area Network (SAN) storage is designed to provide block-level data access to servers, appearing to the operating system as a locally attached hard drive. Huawei OceanStor SAN solutions (both FC-SAN and IP-SAN) are optimized for high-performance, low-latency applications.

Databases (Option C), such as Oracle, SQL Server, and DB2, are primary use cases for SAN storage because they require high IOPS and low latency for transactional processing. The block-level access allows the database management system to have granular control over data placement and caching.VMware virtualization (Option B)is another core scenario. SANs provide the shared storage necessary for advanced features like VMotion, High Availability (HA), and Distributed Resource Scheduler (DRS). In these environments, multiple ESXi hosts connect to a centralized SAN to access VMFS (Virtual Machine File System) volumes. While Option A (Big Data) and Option D (File Sharing) often use Distributed Storage (OceanStor Pacific) or NAS, the high-concurrency, structured nature of Databases and Virtualization makes them the definitive scenarios for SAN.

Direct-Attached Storage (DAS) is a traditional storage architecture where storage devices are connected directly to a host server. Huawei documentation defines the following key characteristics:

Direct Connection (Option C):DAS connects to the server via internal or external interfaces such as SATA, SAS, or SCSI, rather than through a storage network.

No Network Devices (Option A):Because it is a 1-to-1 connection, it does not require Fibre Channel switches or Ethernet switches to facilitate the link between the host and the storage. This makes it simple and cost-effective for small-scale deployments.

Block Storage Services (Option B):Like a SAN, DAS provides block-level access. The server’s operating system manages the file system (NTFS, EXT4, etc.) directly on the provided blocks.

While a server attached to DAS can share its files over a network (becoming a file server), the DAS itself is not a "File Storage Service" (Option D). In Huawei’s hierarchy, file services are the domain ofNAS (Network Attached Storage), which provides shared access to files via protocols like CIFS/SMB or NFS.

According to Huawei’s BCManager and HyperReplication guides, "incorrect" statements must be identified to understand the distinction between disaster recovery (DR) and active-active solutions. Option B is incorrect because while HyperMetro supports automatic transparent failover (zero RTO) using a Quorum Server, standard synchronous remote replication typically requires manual intervention or third-party management software to trigger a switchover when the primary site fails. In synchronous replication, the secondary LUN is usually in a read-only state and cannot take over automatically without administrative action.

Option D is incorrectbecause it describes an "Active-Active" state. In a standard Remote Replication pair, only the primary LUN is accessible for host I/O (Read/Write), while the secondary LUN is locked to maintain data consistency. Only theHyperMetrofeature allows both LUNs in the pair to provide simultaneous read and write services to application servers across different sites. Regarding distance, while asynchronous replication is physically less constrained, synchronous and HyperMetro technologies are strictly limited by latency (typically requiring round-trip time <10ms and distance within 100km to 300km depending on the specific product line) to avoid severe application performance degradation.

NVMe over Fabrics (NVMe-oF) using the RoCE v2 (RDMA over Converged Ethernet) protocol is a high-speed communication technology supported by Huawei OceanStor Dorado systems. Option B is correct because RoCE v2 utilizes RDMA, which allows data to be transferred directly from the memory of one computer to another without involving the CPU of either system. This significantly reduces latency and CPU overhead compared to traditional iSCSI.

Option C is correctbecause RoCE v2 requires a "Lossless Ethernet" environment to function correctly. Traditional Ethernet (Option A) is a "best-effort" delivery system that allows for packet drops during congestion; however, RDMA protocols are highly sensitive to packet loss. To support RoCE v2, the network must implement Data Center Bridging (DCB) features like Priority Flow Control (PFC) and Enhanced Transmission Selection (ETS) to ensure a zero-packet-loss environment. Regarding cost (Option D), RoCE v2 often leverages existing Ethernet infrastructure, making it generally more cost-effective than deploying a dedicated Fibre Channel (FC) fabric, which requires specialized HBAs and FC switches.