Paging Rates

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Paging Rates

This section reports paging subsystem or memory management metrics. This data is collected from OpenVMS performance statistics.

Page Faults: The total number of page faults per second (both hard and soft) during the reporting interval. This includes system faults.
System Faults: The number of page faults incurred in system space per second during the reporting interval. The following are examples of system components that are pageable in system space: XQP caches, logical name tables, process page tables, global page table, and some OpenVMS executive code, for example, RMS. System Fault is a special designation for a page fault, in addition to the types of faults described below.
Pages Read: The number of pages read per second to resolve page faults during the reporting interval. Note that this may be from a page file, an image file, or a file-backed global section.
Read I/Os: The number of page read I/O operations per second during the reporting interval.
Pages Written: The number of pages written per second to disk during the reporting interval, including pages written to the swapping file, to mapped image sections, and to the paging file for modified page writing. Not included are pages written to user files (RMS).
Write I/Os: The number of page write I/O operations per second during the reporting interval.
Free List: The number of page faults per second resolved from the free list during the reporting interval.
Modify List: The number of page faults per second resolved from the modified list during the reporting interval.
Dzero Faults: The number of page faults per second resolved as demand zero pages during the reporting interval.
Gvalid Faults: The number of page faults per second resolved as valid global pages (already in memory) during the reporting interval.
WritIn Prog: WritIn Prog faults are the number of page faults per second resolved from pages currently being written to disk.
Hard Faults: The percentage of Page Faults that required a read from disk. This is (read I/Os)/(page faults) expressed as a percentage.
Soft Faults: The percentage of page faults that were resolved from memory, that is, without reading from disk. This is equal to (100 - hard faults) percent.