Re: [PATCH] Clustering indirect blocks in Ext3

[Andreas Dilger]

On Nov 15, 2007  23:02 -0800, Andrew Morton wrote:
> So we have a section of blocks around the middle of the blockgroup which
> are used for indirect blocks.
> 
> Presmably it starts around 50% of the way into the blockgroup?
> 
> An important question is: how does it stand up over time?  Simply laying
> files out a single time on a fresh fs is the easy case.  But what happens
> if that disk has been in continuous create/delete/truncate/append usage for
> six months?

In the ext4-devel discussion, I asked about placement of the reserved
blocks.  Placement at the beginning of the group showed at worst
marginally less performance and in some cases better performance.
I suspect putting the reserved blocks at the beginning of the group
would have a better long-term effect on performance because they are
not in the middle of large contiguous allocations in the middle of
the group.

Cheers, Andreas
--
Andreas Dilger
Sr. Software Engineer, Lustre Group
Sun Microsystems of Canada, Inc.

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