You are troubleshooting high CPU use on a FAS8200 with all SAS HDDs. You have SAN hosts with LUNs in a volume named vol1. You want to reduce CPU use and maintain storage efficiencies. Referring to the exhibit which three actions will accomplish this task? (Choose three.)
A. Disable compression.
B. Enable cross-volume deduplication.
C. Disable inline deduplication.
D. Enable post process deduplication.
E. Enable data compaction.
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Kind of weird answers, as for FAS and HDD we should put only post-processing efficiencies.
From netapp docs:
– Enabling data compaction on a volume on an HDD aggregate uses additional CPU resources
– Inline Compression – Inline compression is useful for customers who aren’t as performance sensitive and can handle some impact on new write performance as well as on CPU during peak hours.
– Dedup – Inline deduplication might not be a good candidate for entry-level systems in which there is just enough
memory to meet client I/O SLAs. Postprocess deduplication can be considered in such cases. In general,
NetApp does not recommend deduplication for use cases in which data is overwritten at a rapid rate.
So basically cross volume background dedup and post-process dedup should be enabled to save CPU. But with that answers (cross volume dedup not defined), I would go with A/C/D , as we have anyway to disable inline and enable post dedup only, and we should disable compression as it gives good load on cpu. After all we are maintaining storage efficiences, not the same, but still..
Why E? TR-4476 says “Data compaction by itself does not have any additional performance overhead, but because data compaction also tries to compress 4K blocks that are skipped by inline compression, there could be an additional 1% to 2% CPU cycles consumed”.
Because inline compression = true, Data compaction could consumes an additional 1% to 2% CPU cycles.
C,E,D