Re: XFS: how to NOT null files on fsck?

[Nathan Scott]

On Fri, Jul 09, 2004 at 09:37:48AM -0700, L A Walsh wrote:
> It's a feature! :-)
> 
> It's been in the code for years to randomly write nulls to some files 

Pfft, nonsense.  The problem relates to an updated inode size
being flushed ahead of the data behind it (hence a size update
can make it out before delayed allocate extents do, and we end
up with a hole beyond the end of file, which reads as zeroes).

> Apparently not easily reproduced, no one has a clue why it does it.  
> Just does. 

No, its actually well known why it behaves this way.
We are looking into ways to address this, and have some
ideas - the trick is fixing it without hurting write
performance - which we will do, its just not trivial.

There are several techiques to reduce the impact of this
behaviour, as others have described (or see the linux-xfs
archives).

cheers.

-- 
Nathan
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