lightly loaded system eats swap space

tech-lists tech-lists at
Mon Jun 18 12:27:26 UTC 2018

On 18/06/2018 09:08, Erich Dollansky wrote:
> Hi,
> On Sun, 17 Jun 2018 23:19:02 +0100
> tech-lists <tech-lists at> wrote:
>> freebsd-11-stable r333874, ZFS raidz1-0 (3x4TB disks), 128GB RAM,
>> Swap: 4096M Total, 3502M Used, 594M Free, 85% Inuse
> this might not be related but I noticed that your swap space is small
> compared to RAM size. I noticed on a much smaller Raspberry Pi, that it
> runs into trouble when there is no swap even there is enough RAM
> available. Is it easily possible for you to add some GB of swap space
> and let the machine run then?
> How much swap do the other machines have?


Yes, the machine with the problem uses the default 4GB swap. That's all 
the swap it has. The machine without issue has a swapfile installed on a 
SSD in addition to the default 4GB swap.

problematic machine:
Device          512-blocks     Used    Avail Capacity
/dev/ada0p3        8388608     3.3G     714M    83%

machine without a problem, it has swapfile installed:
Device          512-blocks     Used    Avail Capacity
/dev/ada0s1b       8262248     1.7G     2.2G    44%
/dev/md0          65536000     1.9G      29G     6%
Total             73798248     3.7G      32G    10%

I added the swapfile a long time ago on this machine due to the same issue.

But my problem isn't so much an out of swapspace problem; all this is, 
is a symptom. My problem is "why is it swapping out at all on a 128GB 
system and why is what's swapped out not being swapped back in again".


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