Re: Less disk space with reiser4?

[Hans Reiser <reiser@namesys.com>]

Alex Zarochentsev wrote:

>On Mon, Apr 11, 2005 at 04:30:53PM +0200, Stefan Andersson wrote:
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>>Hi,
>>
>>I have a disk array wich I used reiserfs(v3) on, and got 932G.
>>Now I started to test reiser4 on it and get less space, 886G.
>>
>>Is it suppose to be like this or is there something wrong?
>>    
>>
>
>reiser4 reserves 5% of disk space.  
>
>That is so because of delayed block allocation impelented in reiser4.  Actual
>block allocation is done near the transaction commit, it means the allocation
>has to be reliable -- we can't return ENOSPC because the write(2) call when we
>could return an error was already completed successfully.  
>
>The reserved space makes the allocation reliable because it covers possible
>insertions (and growing of the internal reiser4 tree) of new extent items
>insertions on a highly fragmented fs.
>  
>
It also improves performance to ensure that at least 5% is free.

>  
>
>>I'am using linux 2.6.11.4 and default settings for mkfs.reiser4 and 
>>mkfs.reiserfs,
>>and reiser4 patch from 2.6.11-mm3.
>>
>>//Stetan
>>
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