This content has been marked as final. Show 6 replies
Nnnnnnnnnnoooooooooo such thing. But google for Cary Millsap paper "Thinking Clearly About Performance."
Edit: If it's benchmarks you're asking about, see http://kevinclosson.wordpress.com/2012/02/06/introducing-slob-the-silly-little-oracle-benchmark/
Edit 2: I didn't put the slob reference in at first because it is contention that causes many performance problems, and maximal i/o is not an indicator of that.
Edited by: jgarry on Mar 13, 2013 2:09 PM
Edited by: jgarry on Mar 13, 2013 2:10 PM
user622061 wrote:The "limit" has NOTHING to do with Oracle RDBMS & has everything to do with the disk sub-system.
All in the title.
How to find the xxxxbytes/second that generate big perfomance problem on the database ? ....
I'm searching for the "limit" in term of io to not exceed, otherwise the database suffer of performance problem.
The sub-components (the number & type of hardware interfaces between the CPU & disk drives,
the number of disk drives, the speed of the disk drives, how they are mapped & managed by any Volume Manager) influence the maximum & sustained data transfer rate to the database.
Did you take a look at the link in jgarry's reply? That would seem to do what you want.
If you are looking at a single number, though, you're going to have problems. The rate of data you can read from any set of disks via random single-block reads is going to be very different than the rate of data you can read from that same set of disks doing multi-block reads (i.e. table scans) for example. And then there are issues with different types of writes as well.
I like your answer.
You are right.
In other words, the IO performance problem comes from CONTENTION not for reaching maximum reads per seconds. Are you agree ?
If so, what is the indicator from database ( metric, stat, event) we can measure to check if our server is suffer for IO Contention ?
I think to the IO events Like 'db file sequential" for every current session ?
If yes, what is the threashold of this event that causes performance problem ?