Virtual memory efficiency

Command: sar -B

      %vmeff
	     Calculated  as pgsteal / pgscan, this is a metric of the
	     efficiency of page reclaim. If  it  is  near  100%  then
	     almost  every  page  coming off the tail of the inactive
	     list is being reaped. If it gets too low (e.g. less than
	     30%)  then the virtual memory is having some difficulty.
	     This field is displayed as zero if no  pages  have  been
	     scanned during the interval of time.

      pgscand/s
	     Number of pages scanned directly per second.

      pgsteal/s
	     Number  of  pages  the  system  has reclaimed from cache
	     (pagecache and swapcache) per second to satisfy its mem-
	     ory demands.