OSS Performance Monitor Overview

The following diagram shows the relationship between the various processes in the OSS environment and the applicable OSS Performance Records.

An application running in the OSS environment makes calls to access OSS files through function calls in the OSS File-system Library. An OSS name server then locates the file within the correct fileset, based upon configuration information supplied through the fileset’s catalog.

An OSS file manager process runs on each processor, it automatically:

  • Allocates and initializes the PXS (POSIX Shared Segment) extended segment and OSS file-system cache. The PXS extended segment is used to share OSS File-system data structures within that processor. The OSS File-system cache is used to buffer data transfers between the OSS disk files and an OSS application.

  • Satisfies OSS regular file cache-related requests from disk processes.

  • Satisfies OSS memory management requests from the NonStop Kernel memory manager.

Disk processes can also use data caches. The use of disk process caching determines whether OSS File-system caching can be used.

An OSS name server also maintains a cache of the most recently resolved names for its file sets.

Data Collection

The data collected for the Records can be used to indicate the usage of various cache allocations and whether the system would benefit from adding an additional Name Server process, moving a particular application process, or increasing the amount of cache available to the various processes.

The data is obtained using various built-in processes, these are described in How Prognosis Collects Data for OSS Performance Monitor.

Each section within the OSS process can be monitored using the following Records:

Client Program Processor

OSS Performance Monitor utilizes the NonStopMeasureOssCpu (OSSCPU) record to provide information about the OSS elements that operate in each processor of the system, such as, POSIX Extended Segment usage details, OSS file system information and details of the OSS Pipe processes. In addition, the NonStopMeasureOssPipe (OSSPIPE) record is used to obtain OSS Pipe Server counters from the MEASURE OSSCPU entity.

OSS Performance Monitor can monitor for items such as:

  • Named Pipe (FIFO) usage,

  • PIPE usage,

  • POSIX Shared Segment (PXS) usage,

  • File system cache usage.

File Disk Volume Processor

OSS Performance Monitor utilizes the NonStopMeasureDiskFile (DISKFILE) record to supply space and disk rate statistics for disk volumes, including:

a)   Full Guardian names for Guardian files or OSS pathnames for OSS files.

b)   Details of Block Write operations.

c)   Cache Callback information, including the number of callback requests per second sent by DP2 to the OSS File Manager and the percentage of OSS-BLOCK-WRITES performed as a result of Callback requests.

OSS Performance Monitor can monitor for items such as:

  • Socket Usage.

OSS Name Server Processor

Using MEASURE Collector data, the NonStopMeasureOssNameServer (OSSNS) record provides detailed information about the performance and operation of the OSS Name Server process. This includes Inode and Link cache entry details and details of pipe server and OSS Name server messages.

OSS Performance Monitor can monitor for items such as:

  • Name Server’s InodeCache hit rate too low,

  • Excessive Inode cache hits.

Catalog Disk Volume Processor

The NonStopOssFileSystem (OSSFLSYS) record is used to provide information on OSS file sets.

OSS Performance Monitor can monitor for items such as:

  • FILESET usage.

Provide feedback on this article