really strange ext4 behavior

[Ric Wheeler]

On 02/13/2011 01:29 PM, Dennis Jacobfeuerborn wrote:

snip

>>
>> Good to hear that it worked!
>>
>> Note that the barrier code makes your data safer, so you should run with it on
>> by default (unless you really don't care about the file system).
>
>
> If ext3 was running fine without barriers for all these years why is this such 
> a problem with ext4? Does ext4 do something differently that barriers are now 
> required?
>
> Regards,
>   Dennis

ext3 has a default behaviour that lets is magically flush out the data every so 
many seconds. It also has supported barrier mode (and has done for years, other 
distros like opensuse have defaulted barriers on long ago for ext3 as well).

Even with the magic thread that ext3 has, you really do want to run with 
barriers enabled for data integrity.

ext4 is actually faster to repair than ext3 (up to 10 times faster in my testing) :)

ric