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Date: Thu, 4 Sep 2003 13:25:23 -0700 (PDT)
From: Julian Elischer <julian@elischer.org>
To: Andrew Kinney <andykinney@advantagecom.net>
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Subject: Re: 20TB Storage System (fsck????)
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On Thu, 4 Sep 2003, Andrew Kinney wrote:
> > 
> 
> Our experience has been that with 4GB of RAM (or more) you 
> really must increase your KVA to 2GB, leaving only 2GB of UVA.  
> So, I would concur with what Julian said.
> 
> <ducks his head to avoid the rotten tomatoes that are sure to be 
> thrown> ;-)
> 
> With the lack of third party filesystem support in FreeBSD, might 
> you be better served by looking at a Linux system running 
> ReiserFS or one of the other file systems designed for such 
> behemoth disk systems?
> 
> These days, I think Sun even gives away Solaris licenses with their 
> low end x86 servers, so that might even be an option.
> 
> UFS is great, but there are other filesystems out there that have 
> already addressed such problems from their use in academic, 
> government, and scientific computing where gigantic filesystems 
> tend to be more prevalent.
> 

UFS2 will make the filesystem..
All we need is a way to FIX such a filesystem.

My brief analysis of this indicates that a 'serial' fsck should be
possible.

What this would do is read through the filesystem metadata, creating 
several 'list' files on another filesystem. These would then be
duplicated and sorted on  several different fields, and then
recombined in a 'merge' manner, to produce lists of unallocated files,
bad directory entries, duplicate allocated blocks etc. etc.

This would probably be workable in a similar order of magnitute
of time as a normal fsck, except 'offline' and able to handle a much
larger filesystem.

julian