Re: blockfile access patterns logging

From: Jens Axboe
Date: Thu Jan 08 2004 - 09:09:50 EST


On Thu, Jan 08 2004, bert hubert wrote:
> Jens,
>
> For some time I've wanted to log exactly what linux is reading and writing
> from my harddisk - for a variety of reasons. The current reason is that my
> very idle laptop writes to disk every once in a while (or reads, I don't
> know).
>
> Now, conceptually this should not be very hard, but I'd like to ask your
> thoughts on where I might insert some crude logging? There are lots of
> places that might be better or worse for some reason.
>
> I'd love to be as close to the physical block device as possible, short of
> rewriting actual IDE drivers.
>
> Any tips? Or is this idea crazy?

If you have the laptop mode patch (it's in 2.4 current, and in 2.6-mm as
well), then you can enable block dump by echoing 1 to
/proc/sys/vm/block_dump - this will dump all reads/writes to any device
in the system. Sounds like this is what you want.

--
Jens Axboe

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