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Re: Advice about ext3, please



On 2009-03-08_13:41:53, Lists wrote:
> Steven Demetrius wrote:
>> Paul E Condon wrote:
>>> I'd like some confirmation, or refutation, of some reasoning:
>>>
>>> I have a USB external hard drive. It came with vfat fs, but I want to
>>> write an ext2/3 fs on it. All my internal HD are ext3, but should this
>>> one be ext3, also? Doesn't ext3 essentially write everything twice,
>>> first to the journal, and then to the actual target location? This is
>>> OK with an internal bus interface from the CPU to the HD, but USB is
>>> not so fast. So I think I should not use ext3 for this HD. Is this
>>> correct?
>>>
>>> TIA
>>
>> Basically ext3 is ext2 with Journaling. Journaling basically safe-guards 
>> against power failure and system crashes. It is well suited for system  
>> partitions and partitions that are being used most of the time your  
>> computer is on.
>>
>> Journaling uses significantly more disk space and does not allow for  
>> deleted file recovery. IT uses more resources that ext2. Journaling does 
>> not write everything twice. It keeps track of the file system which  
>> makes recovery fast and more reliable than file systems without 
>> Journaling.
>>
>> I recommend the following:
>>
>> ext3 - for system partitions and data partitions which are in use most  
>> of the time (/, /home, /var, etc. if they are separate partitions or  
>> drives).
>>
>> ext2 - for backup, removable, partitions rarely used, etc.
>>
>> If your USB external is for backup or file transfers then I recommend  
>> using the ext2 file system on it. Logic being that if your USB external  
>> data gets corrupted then you still have a copy of the data on another  
>> partition.
>>
>> FYI:
>> Some people confuse backup with archiving. They will make copies of  
>> their data and store it away until they have data problems with the  
>> system. This is archiving.
>> Backup is a never ending routine whether done once a week or one a month 
>> and also include regular data integrity checks of the backups.
>>
>>
>
> Correction:
> Journaling file system does write data twice.
> ttp://en.wikipedia.org/wiki/Ext3

This is an interesting reference. I think I am convinced that journaling
in Linux is -not- a finished story.

Thanks for pointing it out.

-- 
Paul E Condon           
pecondon@mesanetworks.net


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