On 11/11/06, Gary Winiger <[EMAIL PROTECTED]> wrote:
  This case enhances Solaris Zones[1] and builds upon recent work to
  improve the integration between Zones and Solaris Resource
  Management[2].  The case addresses an existing RFE[6], which requests
  a mechanism to limit system swap reserved by a zone.  The case also
  proposes extensions to [2], which will make swap reservation and
  locked memory resource controls easy to configure on a zone via

I'm not sure if this is exactly the right place to bring this up, but
there needs to be some clarity to the user community about the
definition of swap.  Due to the fact that it is not essential to the
discussion of the particular ARC case, PSARC-EXT has not been Cc'd.

The key places that the term "swap" is exposed to users currently is
vmstat(1M) and swap(1M).  A search through the relevant sysadmin
guides and grepping through /usr/share/man turns up this somewhat
unapproachable definition in "System Aministration Guide: Devices and
File Systems":

   The Solaris OS uses the concept of virtual swap space, a
   layer between anonymous memory pages and the physical
   storage (or disk-backed swap space) that actually back these
   pages.  A system's virtual swap space is equal to the sum of
   all its physical (disk-backed) swap space plus a portion of
   the currently available physical memory.

The man pages for vmstat and swap are not especially clear as to
whether they are talking about swap space (blocks in a swap device) or
"virtual swap space", a term that I have only seen in the Devices and
File Systems book.  That, combined with the fact that "devices and
file systems" is not the first place a person would expect to find
this information, frequently leads to a misunderstanding of what the
definition of "swap" is.

As prstat is changed and resource controls are added to limit swap
reservations, it would be extremely helpful to ensure that swap is
clearly defined.  This likely includes a definition in a man page
(time for swapfs(7s)?) and references to that definition in relevant
man pages.


Mike Gerdts
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