Re: Resier Fragmentation Effects (was compression vs performance)

[Hans Reiser <reiser@namesys.com>]

Chris Mason wrote:

>On Fri, 2004-04-09 at 01:53, Hans Reiser wrote:
>  
>
>>Burnes, James wrote:
>>
>>    
>>
>>>I thought nearly all filesystems designed since Berkeley FFS were nearly
>>>immune to fragmentation problems.
>>>
>>>After reading the following analysis at Harvard, it seems that
>>>fragmentation is still a problem.
>>>
>>>http://www.eecs.harvard.edu/~keith/research/tr94.html
>>>
>>> 
>>>
>>>      
>>>
>>Yeah, I wish I had read this in 94.  V3 suffers from the same problems 
>>as FFS does as described in the abstract (all that I read, sorry about 
>>that, I really am a bit busy, so unless someone suggests I should read 
>>more.... ) .  V4 cures it though.
>>    
>>
>
>I put out some patches last week that try to deal with this in v3. 
>
Describe the algorithmic changes please.

> Take
>a look through the archives for mail from me.
>
>The v3 patches are an attempt to do better under common workloads.  I
>think they are a big improvement, and I doubt there's much more that can
>(or should) be done beyond simple tweaking.
>
>v4 does a better job, and even if it doesn't, it should at least have
>enough info in the metadata such that any problems can be fixed.
>
>-chris
>
>
>
>
>  
>


-- 
Hans