Capturing I/O traces

[Ivan Voras]

Fluffles wrote:

> One thought that comes to mind is the gnop geom class; with verbose mode
> this provides a text log of all the I/O accesses. But it does not
> provide the exact time/concurrency etc, only the offset, length, I/O

What do you mean by "time" and "concurrency"? You do realize that
requests are serialized on the low level?

> action (read/write) and the serial order of those requests. And even

You mean when the request was actually completed? Hmmm, it shouldn't be
hard to add...

> with this information it's not easy to reproduce them; i would have to
> write an application that reads this log and then be able to reproduce
> it. I was hoping to find a more elegant solution. If you guys know of
> any, please share it with me. :)

Once upon a time I patched ggatel to generate a log (without the time of
completion). Here it is: http://ivoras.sharanet.org/freebsd/ggatel.tgz
(but IIRC that was for early 6-stable, don't know if it would work now).