RAID 2.0+ Chunk, Chunk Group, and Extent Facts
Short answer
B A chunk group is a logical set of chunks on different disks; extents, not chunk groups, are the storage-pool allocation unit and default to 4 MB.
Question
Key Takeaways
It tests the RAID 2.0+ hierarchy and default sizes, with the main trap being the swap between chunk, chunk group, and extent roles.
RAID 2.0+ organizes physical disks into chunks, chunk groups, and extents. This page confirms that a chunk group is the logical set of chunks across disks, so statement B is the only true option.
Common mistake: A common error is choosing C because chunks are fixed-size disk divisions; in RAID 2.0+ the chunk group, not the individual chunk, is the basic unit of a RAID group.
Expert Analysis
Stem qualifiers point to exact RAID 2.0+ definitions This is a “choose all that apply” item, so every option must survive both the RAID 2.0+ hierarchy and the details about default sizes and allocation units. Huawei’s model divides each physical disk into fixed-size chunks (4 MB by default), groups chunks from different disks into a chunk group, and carves a chunk group into extents; the extent is the space-allocation unit in a storage pool. The deciding phrases are “4 KB by default,” “basic units of a RAID group,” and “minimum unit for applying for and releasing space.”
Option B is the only survivor B says a chunk group is a logical set of chunks on different disks. That matches the RAID 2.0+ definition directly: chunks from separate disks are combined into a chunk group, which then serves as the RAID building block. No size or allocation qualifier contradicts it, so B is correct.
Why A, C and D fail A is close on structure—an extent is a fixed-size block within a chunk group—but the default size is 4 MB, not 4 KB. C confuses the layers: chunks are fixed-size divisions of a disk, but the chunk group, not the individual chunk, is the basic unit of a RAID group. D swaps the allocation unit: it is the extent that is the minimum unit for applying for and releasing space in a storage pool, not the chunk group. A supplied comment suggests BC and correctly notes the 4 MB extent default and the extent’s allocation role, but it still accepts C’s chunk/RAID-group claim; the official hierarchy rules C out.
Exam takeaway Memorize the chain disk → chunk → chunk group → extent, along with the 4 MB default and which layer owns allocation; then letter B is the single true statement.
Exam Strategy
For RAID 2.0+ definition questions, first sketch the hierarchy disk → chunk → chunk group → extent and label the default sizes (chunk 4 MB, extent allocation unit). Then test each option against one layer at a time; a statement that assigns the RAID-group building block to a chunk or the pool allocation unit to a chunk group is a deliberate layer swap. Treat a “choose all that apply” stem as permission to return one letter, and do not add C simply because it contains a correct first clause.
Frequently Asked Questions
What is the difference between a chunk and a chunk group in RAID 2.0+?
What is the default extent size and allocation role in RAID 2.0+?
Why is option D false for RAID 2.0+?
Community Votes
100% of anonymous learners picked answer B. Votes are pick records left by other test-takers — they are not the verified answer.
Discussion 1 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 1
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10c5cfe 👍 1extend default size is 4MB not KB. extent is the minumum unit in a storage pool.
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