I am afraid I can't post a definitive article to this list as some of
you requested but I did learn some useful things :
swap -s reports virtual swap info ie, backing store + that part of
memory which is not used for kernel, /tmp etc
* Swap is used for virtual memory pages that have vnodes NOT pointing to
a UFS inode - things like heap, shared mem etc. These are called
anonymous pages
* The use of malloc makes a reservation of swap space (see "reserved"
from swap -s) but only the actual use of the space transfers the
reservation to an actual allocation.
* There is some user control over the amount of memory kept out of swap
for the rest of the system. See Swapfs_minfree. Swapfs uses this at
startup & it is set to 2M or 1/8 total mem (whichever is larger).
* Solaris will use disk based virtual swap before is uses memory VS
* Several people were able to get their swap components to match between
swap -s & vmstat - I still cannot (even after using disk blocks AND
pages as the multiplier) - maybe I have a bug somewhere!!
* It was suggested that my /tmp could account for the discrepancies I
observed. My /tmp was only a few MB - I don't think that is the whole
story.
For more info, try some of these : *
http://www.sun.com/sunworldonline/swol-01-1998/swol-01-insidesolaris.html
* Sunsolve infodoc number "14120", FAQ number 1538, Solaris
2.x Q&A document 1013, and the Sun Technical Bulletin number 1130
(chapter 6). (thanks Richard Roberto for the refs)
*
http://www.sun.com/sunworldonline/swol-12-1997/swol-12-insidesolaris.html
*
http://www.sun.com/sunworldonline/swol-09-1997/swol-09-insidesolaris.html
Thanks to :
Joseph S D Yao
Richard Roberto
Rick Kelly
Jeff Graham
Good luck to those of you, like me, that havn't got a clue!!
Regards,
Steve
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