Skip site navigation (1)Skip section navigation (2)
Date:      Fri, 2 Jun 2006 08:55:13 +0100 (BST)
From:      Robert Watson <rwatson@FreeBSD.org>
To:        Kris Kennaway <kris@obsecurity.org>
Cc:        Giorgos Keramidas <keramida@ceid.upatras.gr>, freebsd-current@freebsd.org
Subject:   Re: md /tmp and async mounts
Message-ID:  <20060602085412.R69345@fledge.watson.org>
In-Reply-To: <20060601235740.GA39491@xor.obsecurity.org>
References:  <20060522231437.GC1446@odin.ac.hmc.edu> <20060523133037.GA2908@gothmog.pc> <20060523143013.GA11472@ci0.org> <20060523194106.GA46634@xor.obsecurity.org> <20060524203645.GB13500@gothmog.pc> <20060524203747.GA88742@xor.obsecurity.org> <20060524204617.GA13701@gothmog.pc> <20060601002024.GA1453@gothmog.pc> <20060601210655.GA36389@xor.obsecurity.org> <20060601213527.GA53422@gothmog.pc> <20060601235740.GA39491@xor.obsecurity.org>

next in thread | previous in thread | raw e-mail | index | archive | help
On Thu, 1 Jun 2006, Kris Kennaway wrote:

> On Fri, Jun 02, 2006 at 12:35:27AM +0300, Giorgos Keramidas wrote:
>
>>> I think it should be the default.  I think we should also avoid using -M 
>>> (malloc backing for md) in favour of swap backing because of the panic 
>>> problems - this is too easy to trigger by accident and it makes FreeBSD 
>>> look bad since it looks like a bug.
>>
>> Ok, I'll prepare a patch that enables async and disables -M.  We should 
>> also document the fact that tmpmfs="YES" and varmfs="YES" in rc.conf may 
>> require the presence of at least one swap device by default, and point the 
>> users to -M with a warning if they run FreeBSD without a swap device but 
>> still want to use tmpmfs or varmfs :)
>
> Actually I thought about this and don't think it's the case.  swap backing 
> doesn't use swap unless you have memory pressure, and if you have memory 
> pressure and no swap your system is going to explode regardless.

My feeling is that swap-backed md should have been the default years ago.  We 
could add a sanity test to mdconfig that generates a warning if swap-backed md 
is configured but swapping isn't configured.

Robert N M Watson



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20060602085412.R69345>