Priority Paging Is Not Needed With the New Solaris 8 Caching Architecture

The Solaris 8 operating environment introduces a new file system caching architecture, which subsumes the Solaris 7 Priority Paging functionality. The system variable priority_paging should not be set in the Solaris 8 operating environment, and should be removed from the directory /etc/system when systems are upgraded to the Solaris 8 operating environment.

The new caching architecture removes most of the pressure on the virtual memory system that resulted from file system activity. As a result, the new caching architecture changes the dynamics of the memory paging statistics, which makes observing system memory characteristics simpler. However, several of the statistics report significantly different values, which should be considered when analyzing memory behavior or setting performance monitoring thresholds. The most notable differences are:

• The number of page reclaims is higher, which should be considered normal operation during heavy file system activity.

• The amount of free memory is higher because the free memory count now includes a large component of the file system cache.

• Scan rates are almost zero unless there is a shortage of system-wide available memory. Scanning is no longer used to replace the free list during normal file system I/O.