[Klug-general] Be careful with ext4

[Michael E. Rentell]

Alan Pope wrote:
> 2009/6/27 Michael E. Rentell <michael.rentell at ntlworld.com>:
>   
>> WRONG! As a part of the reinstallation of 2008.1 I noticed a slight
>> change in the 'Which partition to format' routine. It just said that it
>> was reformatting / rather than asking whether to reformat / and /home.
>> So, anyway, I clicked 'yes'.
>>
>> DISASTER! It had not recognised the ext4 file system so it didn't know I
>> had two partitions. It formatted the lot and I lost everything.
>>
>>     
>
> That's far from a problem with ext4, and more a problem with the
> Mandriva installer coupled with user error surely?
>
>   
>> So here's a friendly warning. If you upgrade to ext4 there's no going
>> back gracefully. Also, keep up-to-date backups - disaster comes
>> unexpectedly.
>>
>>     
>
> You _can_ go back from ext4 to ext3, and even back to ext2. It may not
> be something the Mandriva installer supports, but it's certainly
> possible.
>
> http://en.wikipedia.org/wiki/Ext4
>
> "The ext3 file system is partially forward compatible with ext4, that
> is, an ext4 filesystem can be mounted as an ext3 partition (using
> "ext3" as the filesystem type when mounting). However, if the ext4
> partition uses extents (a major new feature of ext4), then the ability
> to mount the file system as ext3 is lost."
>
> Cheers,
> Al.
>
>
>   
Like I said, those with knowledge will smile. The problem is that I 
didn't have that knowledge. my intention is that other simple users can 
be made aware of the problem I encountered.
MikeR