Questions about ZFS Tuning

Jamie Paul Griffin jamie at
Mon Sep 17 17:33:56 UTC 2012

[ Mike Clarke wrote on Mon 17.Sep'12 at 18:19:18 +0100 ]

> On Monday 17 September 2012 13:20:14 Jamie Paul Griffin wrote:
> > I set zfs.zfs.prefetch_disable=0 because some dmesg line suggested/implied
> > it would benefit. I don't recall the exact output now. 
> If you look in /var/run/dmesg.boot you should find the message saying "ZFS 
> NOTICE: Prefetch is disabled by default if less than 4GB of RAM is present; 
> to enable, add "vfs.zfs.prefetch_disable=0" to /boot/loader.conf."
> Since you have 2GB RAM then it's best to leave things as they are with 
> prefetch disabled.

Hi Mike, yes that was the notice I saw which made me add this setting. 

Thanks for the reminder and info.

Best wishes, Jamie.

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