freebsd stable - Apr 2018 - devd out of swap space ? (zfs arc related ?)

On one of my internal nfs test boxes, I have noticed that kernels from
March 28th and April 6th r332100 ended up with devd running out of swap
space and being killed at some point.

First time I thought perhaps a fluke due to some stress testing I was
doing.  But I left the box running over the weekend and Sat AM it died
at 3:51am (perhaps when periodic runs?)

I have lots of free memory, however, ARC is chewing up 27G of the 32G.

CPU:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% idle
Mem: 800K Active, 15M Inact, 9964K Laundry, 30G Wired, 516M Free
ARC: 28G Total, 4996M MFU, 23G MRU, 5440K Anon, 78M Header, 593M Other
     27G Compressed, 28G Uncompressed, 1.04:1 Ratio
Swap: 20G Total, 21M Used, 20G Free

Anyone else seen anything like this on a recent RELENG11 STABLE ?

	---Mike


-- 
-------------------
Mike Tancsa, tel +1 519 651 3400 x203
Sentex Communications, mike at sentex.net
Providing Internet services since 1994 www.sentex.net
Cambridge, Ontario Canada

On Mon, 9 Apr 2018 15:27:45 -0400 Mike Tancsa <mike at sentex.net> wrote
about devd out of swap space ? (zfs arc related ?):
> Anyone else seen anything like this on a recent RELENG11 STABLE ?
I think I have seen something similar last week with a -stable from
somewhen in March. Lots of processes crashed over night due to "out of
swap space" although there appeared to be plenty of both swap and RAM.
Somehow it looked arc-related to me, but I havn't been able to reproduce
it so far (however, I did not try too hard, either ;-).
This is what top shows on the machine right now:

CPU:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% idle
Mem: 2776K Active, 7231M Inact, 31M Laundry, 24G Wired, 934M Buf, 288M Free
ARC: 20G Total, 6678M MFU, 13G MRU, 1060K Anon, 182M Header, 146M Other
     19G Compressed, 82G Uncompressed, 4.24:1 Ratio



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