Re: [PATCH] Clustering indirect blocks in Ext3

Matt Mackall
2007-11-16T07:37:42Z

On Thu, Nov 15, 2007 at 11:02:19PM -0800, Andrew Morton wrote:
> On Thu, 15 Nov 2007 21:02:46 -0800 "Abhishek Rai" <abhishekrai@google.com> wrote:
...
> > 3. e2fsck speedup with metaclustering varies from disk
> > to disk with most benefit coming from disks which have a large number
> > of indirect blocks. For disks which have few indirect blocks, fsck
> > usually doesn't take too long anyway and hence it's OK not to deliver
> > a huge speedup there. But in all cases, metaclustering doesn't cause
> > any degradation in IO performance as seen in the benchmarks above.
>
> Less speedup, for more-and-smaller files, it appears.
>
> 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?

Try Chris Mason's compilebench, which is a decent aging simulation.

--
Mathematics is the supreme nostalgia of our time.