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Date: Tue, 11 Mar 2008 08:47:35 +0100
From: Kris Kennaway <kris@FreeBSD.org>
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To: Zaphod Beeblebrox <zbeeble@gmail.com>
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Cc: freebsd-fs@freebsd.org, current@freebsd.org,
	Thomas Vogt <freebsdlists@bsdunix.ch>
Subject: Re: vm_thread_new: kstack allocation failed with many ZFS FS and
 NFSD
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Zaphod Beeblebrox wrote:
> 
> 
> On Mon, Mar 10, 2008 at 8:30 PM, Kris Kennaway <kris@freebsd.org 
> <mailto:kris@freebsd.org>> wrote:
>  
> 
>     Your kernel has run out of memory.  If you cannot tune kmem_size further
>     then it cannot handle this many ZFS filesystems.
> 
> 
> Roughly how much kernel memory does a filesystem use (even if inactive) 
> --- or did you really mean something like too many pools?
> 
> The ZFS documentation encourages creating filesystems for everything.  I 
> think my (rather beafy) laptop has 20 filesystems now for various tasks 
> --- but I didn't realize there was a non-trivial cost (that is: a cost 
> beyond the mount structure, root vnodes and whatnot)...
> 
> 

Well everything has a memory requirement when you add additional 
instances of it :)  I don't know what the breakdown is for ZFS.

Kris