On Wed, 23 Dec 2009, Yanjun (Tiger) Hu wrote:
Hi Jim,
I think Tony was asking a very valid question. It reminds me
http://developers.sun.com/solaris/articles/sol8memory.html#where.
The question is valid, but the answer will be misleading. Regardless
of if a memory page represents part of a memory mapped file,
traditional filesystem cache, an application heap/stack, or zfs ARC,
it is still caching data that the application has used and may use
again. The zfs ARC is smarter so it is better at discarding the data
which is least likely to be used if there is memory pressure. Even
though the ARC is smarter, there is still an expensive disk access
required to restore that data if the application accesses it again.
I find the 'arc_summary.pl' script available from
http://cuddletech.com/arc_summary/ to be a quite useful tool to see a
memory breakdown, including ARC sizes.
Bob
--
Bob Friesenhahn
bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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