Re: reiserfs logging patches udpated

[Mike Fedyk <mfedyk@matchmail.com>]

Hans Reiser wrote:
> Chris Mason wrote:
> 
>> On Thu, 2004-03-25 at 15:41, Mike Fedyk wrote:
>>  
>>
>>> Chris Mason wrote:
>>>   
>>>
>>>> On Wed, 2004-03-24 at 22:56, Mike Fedyk wrote:
>>>>
>>>>
>>>>     
>>>>
>>>>> And after having the difference of a block level journal (ext3), 
>>>>> instead of a "virtual" journal(reiserfs, jfs, xfs) explained to me 
>>>>> (check the ext3-users archives...) -- and how it can save your ass 
>>>>> when there are hardware problems.  I was convinced and switched 
>>>>> everything back to ext3.
>>>>>       
>>>>
>>>> reiserfs does block based logging ;-)
>>>>     
>>>
>>> I stand corrected.
>>>
>>> Thanks Chris, I feel much better about reiserfs now, especially with 
>>> your ordered/data journaling patches.
>>>   
>>
>>
>> One other point, the current patch set only does data=ordered.  I wanted
>> that fully stabilized before I enabled data=journal.
>>
>> -chris
>>
>>
>>
>>
>>  
>>
> what is a virtual journal?
> 

The basic idea of virtual vs block journals, is that instead of using a 
few bytes to describe what you're changing in (for instance) the inode 
table (or equivalent), ext3 (and reiser3 thanks to info from Chris 
Mason) copies entire inode table block (usually 1-4k depending on block 
size) into the journal.