ZFS Tuning - arc_summary.pl

Barry Pederson bp at barryp.org
Tue Mar 30 15:21:50 UTC 2010

On 3/30/10 9:30 AM, jhell wrote:
> Ill mark this up on my todo. Thanks for the feedback&  I should have
> something committed back within the next couple days, possibly even tonight.
> I never recalculated for this difference as that area of the code was
> just a formatting fix.
> But as Jeremy has pointed out, it would have to verify against
> __FreeBSD_version but since I already pull in the sysctl MIB
> kern.osreldate I should be able to compare to that and say 700000 or
> higher make the above correction.
> As this is mainly ZFS v13 dependent now I don't feel to bad doing what I
> have stated above.
> Thanks again,
> Regards,

Shouldn't the "ARC Size Breakdown" be based on the current size (instead 
of the target size) no matter what?

If the current size was *less* than arc_max, you'd also get an 
nonsensical breakdown - in that case with the "recently used" and 
"frequently used" adding up to *more* than the current size.

It seems to me that the only thing that would be different between newer 
and older FreeBSD version would be whether arc_max would be described as 
a "Hard Limit" or not - which is maybe not that important to show.

If that's all true, then the patch should work for both older and newer 
versions of FreeBSD.


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