Re: File System Performance

Peter J . Braam
2001-11-16T22:10:53Z

I don't think anybody has a large KML to share. Unfortunately, I
suspect in many environments people don't want to give such
information.

We should start logging somewhere.

- peter -

On Tue, Nov 13, 2001 at 01:46:53PM -0700, Andreas Dilger wrote:
> On Nov 12, 2001 17:40 -0700, Peter J . Braam wrote:
> > The KML in fact doesn't record the writes. I don't have a large KML,
> > but it is easy to set one up. Let me know if you need a hand.
>
> We don't actually need to have the data contents, just the file sizes,
> which I think the CLOSE records have, don't they? The one thing I'm
> unsure of is whether you zero the KML as it is "used", or does it keep
> the data from past transactions? At one time we were thinking about
> using "punch" to reduce the actual file size, but I doubt that is in
> place yet.
>
> This is purely to measure the effects of repeated file creation, deletion,
> updates in a real setting over a very long period (e.g. many months/years),
> which is why setting something like this up today won't get us anywhere
> (any large amount of activity would just be synthetic).
>
> Do you think Ron Minnich or the folks at Tacitus would have a KML which
> has been generated on a large server over a long period of time and not
> erased?
>
> > On Mon, Nov 12, 2001 at 05:17:05PM -0700, Andreas Dilger wrote:
> > > On Nov 12, 2001 12:41 -0800, Andrew Morton wrote:
> > > > BTW, I've been trying to hunt down a suitable file system aging tool.
> > > > We're not very happy with Keith Smith's workload because the directory
> > > > infomation was lost (he was purely studying FFS algorithmic differences
> > > > - the load isn't 100% suitable for testing other filesystems / algorithms).
> > > > Constantin Loizides' tools are proving to be rather complex to compile,
> > > > drive and understand.
> > >
> > > What _may_ be a very interesting tool for doing "real-world" I/O generation
> > > is to use the InterMezzo KML (kernel modification log), which is basically
> > > a 100% record of every filesystem operation done (e.g. create, write,
> > > delete, mkdir, rmdir, etc).
> > >
> > > Peter, do you have any very large KML files which would simulate the usage
> > > of a filesystem over a long period of time, or would Tacitus have something
> > > like that?
>
> Cheers, Andreas
> --
> Andreas Dilger
> http://sourceforge.net/projects/ext2resize/
> http://www-mddsp.enel.ucalgary.ca/People/adilger/
>

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