Hi,

I'm trying to do some testing between RHEL5 & 6 (Beta).

I'm finding my application seems to do alot more IO on RHEL6 and I'm trying to find out why...

I've installed blktrace and btrace, and I've got results out.

However, I have a question about one of the output fields in the summary, "IO Unplugs"

Can anyone explain what these are?

On the RHEL5 I get non of these, but on RHEL6 the figure in that field seems to be close to or the same as the "Reads Completed" field.

Not sure if that is a problem or not, and just wanted to understand what 'IO Unplugs' are... as I don't seem to be able to find out anything about them...

Also, I get different states of each IO. On RHEL5 I an IO seems to go from state 'A', to 'Q' to 'C'... but on RHEL6 I seem to never get any 'A' states, and I get lots of 'U' states. I presume the 'U' state equates to the 'Unpluged' totals.

I'm fairly new to blktrace, so I'm not to up on it yet...

Thanks,

Rob D.