Re: Best filesystem for loop-aes

[David <shadoweyez@xxxxxxxxx>]

Thanks for the clarification - so journaled writes with ext3 are safe on
a * block-device * like a standard hard drive?  Have you used ext3
w/loop-aes and shown it to be stable?

Thanks,
David

Daniel Harvey wrote:
> Hi David,
> 
> I think you've misread the readme slightly. It states
> 
>     2.2. Use of journaling file systems on loop device
>     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>     Don't use a journaling file system on top of file backed loop device. Device
>     backed loop device can be used with journaling file systems as device backed
>     loops guarantee that writes reach disk platters in order required by
>     journaling file system (write caching must be disabled on the disk drive, of
>     course). With file backed loop devices, correct write ordering may extend
>     only to page cache (which resides in RAM) of underlying file system. VM can
>     write such pages to disk in any order it wishes, and thus break write order
>     expectation of journaling file system.
> 
> 
> So, feel free to use ext3 on a *_block-device_* backed loop device as
> this guarantees the order of writes which is essential for journal-based
> filesystems.
> 
> i.e.
> OK: ext3 --> loop device -> block device
> BAD: ext3 --> loop device -> file
> 
> Cheers,
> Daniel.
> -- 
> Daniel Harvey <daniel@xxxxxxxxxxxxxxx <mailto:daniel@xxxxxxxxxxxxxxx>>
> 
> 
> On Tue, 2008-02-12 at 21:11 -0800, David wrote:
>> Hi everyone;
>>
>> Been looking on google but can't find a good answer/explanation;
>> What is a "good"/"the best" file system for loop-aes?  The readme states 
>> don't use a journaling system (ie ext3), but ext2 is a pain to do a hard 
>> restart from because of the fsck time.
>>
>> What modern linux file system works well w/loop-aes and has the 
>> convenience of quick recovery and stability?
>>
>> David
>>
>> -
>> Linux-crypto:  cryptography in and on the Linux system
>> Archive:       http://mail.nl.linux.org/linux-crypto/
>>
> 

-
Linux-crypto:  cryptography in and on the Linux system
Archive:       http://mail.nl.linux.org/linux-crypto/