Re: Using fio with blkread data, example needed

From: Jens Axboe <>
Date: Mon, 3 Dec 2007 09:45:54 +0100

On Mon, Dec 03 2007, Joshua Root wrote:
> John Rouillard wrote:
> > I am planning on using fio to simulte a disk load on some diskless
> > clients that will be using NFS rather then local disk as their data
> > source/sink.
> >
> > I have run blktrace on a system with local disks that is currently
> > running the worload of interest. I have the files:
> >
> > sda1.blktrace.0 sda1.blktrace.1 sda1.blktrace.2 sda1.blktrace.3
> >
> > (4 cpu system), but I am not quite sure what to use for an fio job
> > file. Does anybody have any examples I could work from?
> All fio can really do with your trace is replay it against a block
> device. It sounds like you really want to record what's happening at the
> filesystem level rather than the block I/O level.

Yeah, you can't really replay a block device trace against an nfs setup.
You could mimic it to some extent by laying out a file big enough on the
nfs server and then replay the above sda trace against that file.

But I agree with Joshua, there's probably a better fit for what you

Jens Axboe
Received on Mon Dec 03 2007 - 09:45:54 CET

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