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Subject: Re: Troubleshooting kernel panic with zfs
To: Mike Tancsa <mike@sentex.net>, Josh Gitlin <jgitlin@goboomtown.com>,
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From: Shane Ambler <FreeBSD@ShaneWare.Biz>
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Date: Sat, 22 Sep 2018 12:23:06 +0930
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On 21/9/18 10:34 pm, Mike Tancsa wrote:
> 
> Given all the issues with memory pressure perhaps ARC is eating too
> much, I would try artificially limiting it so it does not eat up too
> much RAM.  We had a similar purposed server but with 32G RAM and I found
> one day the system was randomly shooting processes to reclaim RAM
> 
> eg
> pid xxx (yyy), uid zzzz, was killed: out of swap space
> 

I have seen these errors, for me they came when >90% ram is wired.

This is something I reported in bug 229764. While ARC is wired, there is
also a max_wired that limits other wired allocations, these two are
independent and can total more than physical ram.

max_wired defaults to 30% ram, so arc_max should be kept less than 70%

I also had positive results applying review D7538

-- 
FreeBSD - the place to B...Storing Data

Shane Ambler