SG0-001 · Question #19
An administrator notices an occasional spike in disk IOPS beyond what the disks can handle. Worried about application performance, the administrator talks with users, but the effect seems to have gone
The correct answer is D. Controller Cache. Controller cache within a storage array acts as a buffer, absorbing sudden spikes in I/O operations and writing them to the disks at a more consistent rate, thereby preventing users from noticing temporary performance fluctuations.
Question
An administrator notices an occasional spike in disk IOPS beyond what the disks can handle. Worried about application performance, the administrator talks with users, but the effect seems to have gone unnoticed. Which of the following is MOST likely preventing the users from experiencing the effects of the spikes?
Options
- ARedundant Fabric
- BFiber Channel
- CInter-Switch Links
- DController Cache
How the community answered
(42 responses)- A5% (2)
- B10% (4)
- C2% (1)
- D83% (35)
Why each option
Controller cache within a storage array acts as a buffer, absorbing sudden spikes in I/O operations and writing them to the disks at a more consistent rate, thereby preventing users from noticing temporary performance fluctuations.
Redundant Fabric provides high availability and fault tolerance for the network path to storage, but it does not directly buffer or smooth out I/O spikes at the storage array level.
Fibre Channel is a protocol for connecting servers to storage, providing high-speed data transfer, but it does not inherently smooth out I/O spikes caused by the underlying disk limitations.
Inter-Switch Links (ISLs) connect Fibre Channel switches, allowing traffic to traverse the fabric, but they do not provide caching or buffering to mitigate I/O spikes at the storage array itself.
The controller cache (or write cache) in a storage array is designed to buffer incoming I/O requests. When a spike in IOPS occurs, the cache temporarily holds the requests, acknowledges them quickly to the host, and then flushes them to the physical disks at a rate the disks can sustain, effectively masking the spikes from the end-users.
Concept tested: Storage array controller cache function
Source: https://docs.oracle.com/cd/E21619_01/html/E21626/z40003b11802951.html
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