Hi Gianluca,
On Thu, Dec 01, 2005 at 02:28:09PM +0100, Gianluca Rossi wrote:
Hi Henrik, I have seen that hobbit clients collects cpu stats via vmstat, now i think that the cpu information provided by "iostat -c" is more accurate, because it has the "%waiting for i/o" columns, wich is also in the linux version of vmstat. do you think you can add this information?
this was a surprise. I didn't know that iostat's CPU statistics was more detailed than vmstat's.
I have updated the Solaris Hobbit client so it collects the CPU statistics, through a "iostat -c 300 2" command like it does with vmstat. However, changing Hobbit to pick up the I/O wait data is problematic, because the vmstat RRD file for Solaris systems doesn't have this dataset defined. So to use these data, I need to change the layout of the Solaris vmstat RRD - which means you will lose all of the statistics collected until now. This was a bad mistake I made when I first decided on the vmstat layout - I should have made it identical across OS'es, instead of sticking with the old LARRD layout where it was different for each OS. (netstat had the same issue, and there I decided to use a common format).
I can make Hobbit work with a new format, but it will require some more code - so I'll postpone this until after 4.2 is out.
While looking at iostat, I also dug into the disk statistics it can provide. I have never managed to get any meaningful data from the old BB iostat script, so let's do this properly for Hobbit. So far, the client will collect the data - analysing them and doing the graphs comes later.
Regards, Henrik