220-1201 Practice Question: A technician is troubleshooting a server that…

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  The controller will switch to read-only mode.

  Why it's wrong here

  A RAID controller's primary response to a failing cache battery is to protect data integrity without completely halting server operations. Switching to read-only mode would be an overly drastic measure, rendering the server largely unusable for write operations. Instead, the controller typically disables write caching to ensure all data is immediately written to the physical disks, thereby preventing potential data loss during an unexpected power outage, while still allowing full read/write functionality, albeit with reduced write performance.

• ✓

  The controller will disable write caching to protect data integrity.

  Why this is correct

  This is the correct and most common protective action taken by a RAID controller when its battery-backed write cache (BBWC) or non-volatile cache (NVRAM) is failing or depleted. Write caching temporarily stores data in volatile memory before committing it to disk, significantly improving write performance. However, without a functional battery to sustain this cache during a power loss, any data residing only in the cache would be lost. Disabling write caching ensures all write operations are immediately committed to the physical drives, guaranteeing data integrity at the expense of write speed.

• ✗

  The controller will increase the stripe size to compensate.

  Why it's wrong here

  Stripe size, also known as block size, is a fundamental configuration parameter of a RAID array that defines the amount of data written to a single disk in the array before moving to the next disk in the stripe. This setting is established during the initial creation of the RAID volume and is static; it cannot be dynamically adjusted by the controller in response to a failing cache battery. Changing the stripe size would fundamentally alter the array's data layout and would typically require rebuilding the entire array, which is unrelated to cache battery health.

• ✗

  The controller will automatically rebuild the array.

  Why it's wrong here

  Array rebuilding is a process initiated when a drive in a redundant RAID array fails, or when a new drive is added to expand or repair the array. Its purpose is to reconstruct the data from the failed drive onto a new drive using parity or mirroring information from the remaining healthy drives. A failing cache battery, while critical for data integrity during power loss, does not indicate a drive failure or a need to reconstruct array data. Therefore, it does not trigger an array rebuild operation.

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