Important Spectrum Scale parameters

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The Spectrum Scale parameters commonly considered for performance tuning related to ECM workloads are described in detail in the Part 1 white paper that preceded this white paper. Most of the important parameters are related to Spectrum Scale cache usage. The table provided here lists the parameters used in the Part 2 case study, together with their default and tuned values .

Table 1. Important Spectrum Scale parameters used in the Part 2 case study
Parameter Description Value used in Part 2 case study
Pagepool size Used for caching user data and file system metadata (default 1GiB).
  • SD: set to 2 GiB on ECM nodes
  • NSD: 2 GiB on ECM nodes (NSD clients) and 1 GiB for NSD servers
maxFilesToCache Total number of files that can be cached at one time in the pagepool (default 4,000).
  • Set to 20,000 (20k). This value proved as good for this particular ECM workload
maxStatCache Not effective on the Linux platform (default 1,000).
  • Set to a smaller value (512).
blocksize The blocksize of the Spectrum Scale filesystem.
  • Default (256 KiB) was used.
Inode limit The default Inode limit value can become a threshold for the file systems.
  • Was increased to 15M inodes.

For other details, refer to the chapter IBM Spectrum Scale tuning parameters in the Part 1 white paper.