Which filesystem for target?

Which filesystem for target?

[Chris Tapp]

A bit of an open-ended question, but...

Which is the 'best' filesystem to use for an embedded device that's  
using a CF card?

It needs to survive loss-of-power, have a RO root filesystem, allow  
user configuration data to persist and (ideally) only use 'Busybox'  
commands.

This seems to imply the use of a partition for booting (mount RO) and  
a second partition or a loop-device on the boot partition for  
persistent storage.

I would normally go for ext3, but Busybox doesn't support it (afaik).  
The Busybox tune2fs also only supports -L, so I can't stop 'disk needs  
checking after <n> mounts' messages.

Is btrfs a suitable alternative?

Chris Tapp

opensource@keylevel.com
www.keylevel.com

Re: Which filesystem for target?

[Stewart, David C]

Anybody got an answer for Chris?  

(A lot of folks are traveling back from a conference, Chris, so might explain slowness)
Sent from my Blackberry

----- Original Message -----
From: Chris Tapp [mailto:opensource@keylevel.com]
Sent: Friday, October 28, 2011 03:11 PM
To: yocto@yoctoproject.org <yocto@yoctoproject.org>
Subject: [yocto] Which filesystem for target?

A bit of an open-ended question, but...

Which is the 'best' filesystem to use for an embedded device that's  
using a CF card?

It needs to survive loss-of-power, have a RO root filesystem, allow  
user configuration data to persist and (ideally) only use 'Busybox'  
commands.

This seems to imply the use of a partition for booting (mount RO) and  
a second partition or a loop-device on the boot partition for  
persistent storage.

I would normally go for ext3, but Busybox doesn't support it (afaik).  
The Busybox tune2fs also only supports -L, so I can't stop 'disk needs  
checking after <n> mounts' messages.

Is btrfs a suitable alternative?

Chris Tapp

opensource@keylevel.com
www.keylevel.com



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Re: Which filesystem for target?

[Paul Eggleton]

On Friday 28 October 2011 23:11:22 Chris Tapp wrote:
> Which is the 'best' filesystem to use for an embedded device that's
> using a CF card?
> 
> It needs to survive loss-of-power, have a RO root filesystem, allow
> user configuration data to persist and (ideally) only use 'Busybox'
> commands.
> 
> This seems to imply the use of a partition for booting (mount RO) and
> a second partition or a loop-device on the boot partition for
> persistent storage.
> 
> I would normally go for ext3, but Busybox doesn't support it (afaik).
> The Busybox tune2fs also only supports -L, so I can't stop 'disk needs
> checking after <n> mounts' messages.
> 
> Is btrfs a suitable alternative?

Arnd Bergmann gave a talk at ELCE on flash drive performance (something he has 
done quite a lot of research on); I did not attend but Darren and I spoke to 
him later on, and if I recall correctly in his tests btrfs performed the best. 
Hopefully the talk video will be available soon thanks to the folks at Free 
Electrons; in the mean time there's an earlier article by Arnd on this topic 
here:

http://lwn.net/Articles/428584/

Cheers,
Paul

-- 

Paul Eggleton
Intel Open Source Technology Centre

Re: Which filesystem for target?

[Chris Tapp]

On 31 Oct 2011, at 10:16, Paul Eggleton wrote:

> On Friday 28 October 2011 23:11:22 Chris Tapp wrote:
>> Which is the 'best' filesystem to use for an embedded device that's
>> using a CF card?
>>
>> ...
>
> Arnd Bergmann gave a talk at ELCE on flash drive performance  
> (something he has
> done quite a lot of research on); I did not attend but Darren and I  
> spoke to
> him later on, and if I recall correctly in his tests btrfs performed  
> the best.
> Hopefully the talk video will be available soon thanks to the folks  
> at Free
> Electrons; in the mean time there's an earlier article by Arnd on  
> this topic
> here:
>
> http://lwn.net/Articles/428584/

Thanks, that's a very good article that may explain some issues I've  
been seeing.

Chris