Disk Domain Size vs Rebuild Time in Huawei Storage
Short answer
A The rebuild time for a failed disk in Disk Domain B (20 disks) is indeed longer than in Disk Domain A (40 disks) because the smaller domain has fewer disks to distribute the I/O load for data reconstruction.
Question
Key Takeaways
Tests understanding of how distributed I/O resources in larger disk domains accelerate RAID rebuild processes compared to smaller domains.
Determines whether disk domain size affects rebuild speed. Larger domains with more disks enable faster parallel I/O during recovery, making Domain B's rebuild slower than Domain A's.
Common mistake: Choosing FALSE based on the assumption that rebuild time is constant regardless of domain size, failing to account for the increased aggregate I/O throughput provided by additional disks.
Expert Analysis
Rebuild Mechanics in Huawei OceanStor
In Huawei intelligent storage systems, disk domains are logical groupings of physical disks that share resources for parity and redundancy calculations. When a disk fails, the system initiates a rebuild process to restore data integrity using remaining healthy disks.
The Impact of Disk Count on I/O Throughput
The key factor here is how rebuild tasks are distributed. In larger disk domains, the workload of reconstructing lost data is spread across a greater number of active disks. This parallelization increases the aggregate I/O bandwidth available for the rebuild operation. Consequently, having more disks (like in Domain A with 40 disks) allows for faster data retrieval and reconstruction compared to a smaller domain (Domain B with 20 disks), assuming similar disk specifications.
Addressing Common Misconceptions
Many candidates assume rebuild time depends solely on disk capacity or RAID level, ignoring the resource distribution aspect. One comment argues that "rebuilds 1 disk take always the same time," which overlooks the fact that the source of the data during rebuild comes from multiple other disks. With fewer disks, the bottleneck is the limited number of contributors, not the amount of data per se. Another comment correctly notes that if there are more disks, it will be faster due to this parallel processing capability. Therefore, the rebuild in the smaller domain (B) takes longer because it has fewer resources to draw upon simultaneously.
Exam Strategy
When analyzing storage performance questions, always consider resource aggregation. If a task can be parallelized across hardware components, increasing the component count typically improves speed unless a specific bottleneck exists. For rebuild scenarios, remember that more source disks mean higher aggregate read bandwidth.
Frequently Asked Questions
Why does having more disks make rebuild faster?
Does RAID level change this relationship?
Discussion 4 contributions
Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.
From public community threads 4
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oro_blu 👍 2False: rebuils 1 disk take always thw same time even with tons of disks
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ArturNascimento 👍 1 Answered AThe rebuild time for a failed disk usually doesn't directly depend on the total number of disks in the domain, but rather on factors such as: The capacity of the failed disk The speed of the disks in the domain I/O load on the system during the rebuild The redundancy method (e.g., RAID 5, RAID 6) If both domains use disks with the same specifications and configurations, the rebuild time should be similar, regardless of the total number of disks. Therefore, the statement is false.
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Abdurauf 👍 1 Answered Anow RAID version 2.0. Hire A-true! WHen disk is more, it will be faster
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OmarOO7 👍 1If he said logical disk then the correct answer will be [A.True] ?
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