Making vfs.zfs.arc_max setting persist

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Darren David

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Feb 27, 2014
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Hi there-

I've got a new setup with 128GB ram, and I'd like to cap out vfs.zfs.arc_max at around 32GB (I have an 8x10TB RAIDZ2 with ~50TB of usable space). It seems that vfs.zfs.arc_max is set to max RAM - 1GB, and with my rsyncing of data over to this new machine ARC is taking up all the available RAM and causing the entire machine to grind to a halt.

I've tried setting vfs.zfs.arc_max in tunables under both "loader" and "sysctl," and I've also added
Code:
vfs.zfs.arc_max="34359738368"
to /boot/loader.conf, but the setting doesn't persist across reboots in any of these scenarios. I can manually set it using sysctl from the command line and all is well, but none of the means I mentioned seem to persist the setting across reboots. I've got 'autotune" disabled, FWIW.

What am I missing here?

Thanks in advance for any and all help.
 

Chris Moore

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What version of FreeNAS are you using?

Sent from my SAMSUNG-SGH-I537 using Tapatalk
 

kdragon75

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Chris Moore

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I've got a new setup
Did you install the FreeNAS 11.2-RC2 version of FreeNAS? I have seen several reports today of people having problems with it using all the memory and overflowing swap to the point of total system lockup.
I would suggest going back to the stable version, FreeNAS 11.1-U6, because the RC is a "Release Candidate", not really ready for production.
upload_2018-11-18_1-58-33.png
 

Darren David

Explorer
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Feb 27, 2014
Messages
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Did you install the FreeNAS 11.2-RC2 version of FreeNAS? I have seen several reports today of people having problems with it using all the memory and overflowing swap to the point of total system lockup.
I would suggest going back to the stable version, FreeNAS 11.1-U6, because the RC is a "Release Candidate", not really ready for production.
View attachment 26624

Indeed, I am on 11.2-RC2 (I wanted to play with the newest UI and virtualization tools).

What's interesting is that I have vfs.zfs.arc_max set to 32GB in loader.conf but when the system boots checking the value from the C/L it's showing up at 21GB. Which is certainly less than what is was doing before, as you mentioned, which was using up all available RAM.

Is there a sane way to roll back to stable without losing any data?
 
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