I/O monitor - like iptraf but for block devices ?

[Naoki]

Howdy all,

This thread generated no traction on fedora-list so I'll ask here as
there might be more chance somebody here can answer the kernel hooks
related question.

Is there a cool curses app that can tell you which PID is writing to
which file handle, on what device and at what speed ?

I've been wondering how to get this sort of info out of existing tools
(lsof, top, etc) without success. 

Would the right kernel hooks be in place to at least write something
like this ?

iostat is useful, but I'm after something a little more intuitive,
iostat can't handle a PID as an argument for example. 


NAME                  PID                    BLOCKS/W            BLOCKS/R      KB/s    FD 
  "FILE NAME"          DEVICE
httpd                 4836			45		    1          53     13   /var/log/httpd/xxx   
/dev/hda2
And so on..

Diagnosing disk IO problems would be far easier if one had a tool that
could give "at a glace" detail into what is doing what and where..

iostat shows you what disk, or which partition is busy, but not what PID
is doing the i/o. So one must go back to lsof and get a list of open
handles on that partition or device and guess which one is pushing the
ops/blocks.

[Dennis Jacobfeuerborn]

Naoki wrote:
...
>  NAME                  PID                    BLOCKS/W           
> BLOCKS/R      KB/s    FD    "FILE NAME"          DEVICE
>  httpd                 4836			45		    1          53     13   /var/log/httpd/xxx   
> /dev/hda2
>  And so on..
>  
>  Diagnosing disk IO problems would be far easier if one had a tool that
>  could give "at a glace" detail into what is doing what and where.. 
...

I'd like to see something like this too. Maybe Dave Jones could turn his 
"printk hack" (http://kernelslacker.livejournal.com/35270.html) into 
something usable by userland tools?

Regards,
   Dennis

[Dave Jones]

On Mon, Jan 30, 2006 at 01:52:00PM +0100, Dennis Jacobfeuerborn wrote:
>  Naoki wrote:
>  ...
>  >NAME                  PID                    BLOCKS/W            BLOCKS/R  
>  >KB/s    FD    "FILE NAME"          DEVICE
>  >httpd                 4836			45		    1        
>  >53     13   /var/log/httpd/xxx    /dev/hda2
>  >And so on..
>  >
>  >Diagnosing disk IO problems would be far easier if one had a tool that
>  >could give "at a glace" detail into what is doing what and where..
>  ...
>  
>  I'd like to see something like this too. Maybe Dave Jones could turn his 
>  "printk hack" (http://kernelslacker.livejournal.com/35270.html) into 
>  something usable by userland tools? 
It'd be more worthwhile as a long-term goal to write such a tool
as a systemtap script.  There has been some effort already into
doing something like this.

See http://people.redhat.com/berrange/systemtap/bootprobe/

		Dave