Re: Silly question, defrag

[Hans Reiser <reiser@namesys.com>]

Richard Thornton wrote:

>Why doesn't linux use UFS?  I can't understand this.
>
>Richard
>
>
>On Wed, 3 Apr 2002, Ross Vandegrift wrote:
>
>>On Wed, Apr 03, 2002 at 08:08:21AM -0800, Matthew Johnson wrote:
>>
>>>On Wednesday 03 April 2002 00:21, Joe Cooper wrote:
>>>
>>>>"Don't"
>>>>
>>>Well I don't, but when newbies who are used to computing on win32 systems
>>>hear that they may not just accept the word don't. Actually its hard to find
>>>the reasons exactly why one does not defrag.
>>>
>>Depending on the elevator algorithms in Linux (sorry, I'm not very
>>familiar with them), performance can actually be *increased* by
>>some bit of fragmentation.  If the data is spread out over the disk,
>>I've heard it allows some elevator algorithms to improve their queuing
>>stategies.  I'm pretty sure this is the case on Novell Netware.
>>
>>Unfortunately I don't have enough technical knowledge about elevator
>>algorithms to really know if it helps or hurts us.  However, I do know
>>that back in the days when I was just getting into Linux stuff
>>(around 2.0.0-ish era), it was generally said that ext2 driver did basic
>>defrag on write and it limited fragmentation to pathological filesystem
>>usage.
>>
>>Again, not sure that this is still the case.
>>
>>Ross Vandegrift
>>ross@willow.seitz.com
>>
>
>
>
UFS is slower than ext2 by a lot.

Hans