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Date: Mon, 28 Jan 2013 10:11:03 +0800
From: ChenQi <Qi.Chen@windriver.com>
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Subject: Re: [PATCH 09/12] initscripts: inherit volatiles to support read-only rootfs
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On 01/25/2013 10:14 PM, Richard Purdie wrote:
> On Fri, 2013-01-25 at 13:11 +0000, Burton, Ross wrote:
>> On 24 January 2013 08:16,  <Qi.Chen@windriver.com> wrote:
>>> +VOLATILE_DIR = "/var/volatile/lib/urandom"
>>> +VOLATILE_LINK = "/var/lib/urandom"
>> A better solution would be to not attempt to save and restore a seed
>> value that is intended to persist across reboots when it's on a tmpfs.
>>   Putting the urandom seed into tmpfs is just a waste of time.
> I have to wonder why we don't put a union mount tmpfs over /var/lib to
> be honest...
>
> or if we don't want to depend on unionfs, a tmpfs over /var/lib...
>
> Cheers,
>
> Richard
>
>
>
A union mount tmpfs over /var/lib (and maybe /etc) was the first 
solution that came into my mind. Then I saw a bug related to unionfs 
about getcwd() call, and I saw the unionfs was still disabled for live 
images. So I thought "maybe I should not use unionfs".

A tmpfs over /var/lib.
Hmm... I thought about that too. The reason that I didn't use this 
method was that I thought that some directories under /etc might also 
need to be written to.
It turns out that this concern seems unnecessary.

Anyway, I'll try out the tmpfs-over-var-lib method and let you know the 
result.

Thanks,
Chen Qi