What is inline data compression in ONTAP and what is its impact?

• A. Inline compression stores data in compressed form on disk to save space; it may affect write performance depending on workload.
• B. Inline compression decompresses data on read to reduce CPU usage.
• C. It stores data uncompressed but uses higher capacity.
• D. It compresses data to network rather than disk.

Answer: (A)

Inline data compression in ONTAP compresses data as it is written and stores the compressed form directly on disk, so you gain storage savings without a separate post-processing step.

The impact centers on how much your data actually compresses and the workload. If the data is highly compressible, you see substantial space savings with only a modest write-time impact from the compression work. If the data isn’t very compressible, the CPU overhead of compressing can be more noticeable, and the benefit in reduced storage may be smaller. On reads, data is decompressed as it’s retrieved, which uses CPU resources and can affect read latency depending on workload and hardware. Overall, inline compression trades some write (and read) CPU usage for reduced disk footprint, with the balance depending on data patterns and system resources.

Other statements that suggest decompression on reads to reduce CPU, storing uncompressed data, or compressing data over the network don’t describe how inline compression in ONTAP operates.