Fajar A. Nugraha wrote:
On Wed, May 6, 2009 at 10:17 PM, Richard Elling
<richard.ell...@gmail.com> wrote:
Fajar A. Nugraha wrote:
IMHO it's probably best to set a limit on ARC size and treat it like
any other memory used by applications.
There are a few cases where this makes sense, but not many. The ARC
will shrink, as needed. With the new write throttle, the perception of
ARC dominance is significantly reduced. The main reason to limit ARC
today, is to prevent the large page/small page change that can happen if
you need to restart a large-page using application (eg databases).
I got a recommendation to limit ARC size when using zfs in xen dom0.
https://opensolaris.org/jive/thread.jspa?messageID=355579
Is it among the "not many" cases, or is irrelevant today with new
write throttle?
I see no justification in that post for limiting memory use. You can
easily measure memory usage with vmstat and ARC-specific usage
with arcstat and see if you are running into a memory shortfall. If
not, then the recommendation may be misguided.
-- richard
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