Re: ext4 settings in an embedded system

[Artem Bityutskiy <dedekind1@gmail.com>]

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On Thu, 2012-11-15 at 13:01 +0300, Andrey Sidorov wrote:
> On Thu, Nov 15, 2012 at 12:42 PM, Artem Bityutskiy <dedekind1@gmail.com> wrote:
> 
> > We conducted some 3 years ago. Results were quite good for ext4 - in
> > many cases it could recover without a need to run ckfs.ext4, sometimes
> > it was not mountable, but ckfs.ext4 helped.
> >
> > On the opposite, ext3 constantly required ckfs.ext3, and sometimes died
> > so badly that even ckfs.ext3 could not recover it.
> 
> We ran about 6000 cycles of power resets with linux 2.6.37. The test
> was to run 3 tar processes unpacking linux kernel archive and power
> off after about 15 seconds. There were only 3 failures when file
> system couldn't be mounted, but that was due to HDD failure
> (unreadable sector in journal area). e2fsck successfully recovered
> those corruptions. As for software itself, there was no single issue
> and we never needed to run fsck after power loss. So I'd say that ext4
> is very tolerant to power losses at least in 2.6.37 assuming barriers
> and ordered data mode. I however understand this test is quite basic
> and any way results can be different for different kernels.

Very different experience indeed, shoes that everyone has to conduct own
power-cut tests in own system. I did not say that we were running on
eMMC.

-- 
Best Regards,
Artem Bityutskiy

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