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From: Bob Bishop <rb@gid.co.uk>
To: Ivan Voras <ivoras@freebsd.org>
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Date: Tue, 17 Mar 2009 14:37:26 +0000
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Subject: Re: A trio of problems
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On 17 Mar 2009, at 13:59, Ivan Voras wrote:

> Bob Bishop wrote:
>> Hi,
>>
>> On 16 Mar 2009, at 23:28, Ivan Voras wrote:
>>
>>> 1. I'm trying to start 1000 jails for demonstration purposes (a
>>> presentation), but I can reliably panic the kernel when somewhere
>>> between 400 and 600 jails are started. [etc]
>>
>> On 17 Mar 2009, at 01:37, Ivan Voras wrote:
>>
>>> ZFS doesn't influence it - the same problem happens without ZFS on  
>>> the
>>> system (though I can create a few hundred more jails without ZFS  
>>> before
>>> the kernel panics...).
>>
>> In which case, given how memory-hungry ZFS is, it looks like your
>> problem is with exhausting some memory resource.
>
> It did occur to me but if it is, why didn't it fail in an obvious way
> (e.g. kmem_map panics with ZFS),

Dunno

> and how to tune it so if works? This is
> AMD64 with 0.5 GB - 1 GB memory in the Free bin when it panics.

I'd suggest increasing kernel mem but I don't know if/how that's  
tunable on amd64.

--
Bob Bishop
rb@gid.co.uk