Re: what is "kfk: async disk IO"?

Freek,

thank you for your clarification.
Currently I'm not so much on the performance tuning side. It's more a kind of 
troubleshooting, where I still does not know how to catch the situation.
Some minutes after my observation the instance hang as all sessions where used 
- not even sys could logon. (yes, prelim worked, but that's not the issue here).
No, my colleague did not create a systemdump or hanganalyze or similar.... 

Even it's only a 'test' system we had to restart the instance. Without any big 
investigation. 
Now I'm searching what this "kfk: async disk IO" is. Maybe someone has some 
infos about P1, P2, P3. I will try to grab some informations out of ASH or 
other resources, based on this.

 Martin 

Am 07.12.2010 um 10:42 schrieb D'Hooge Freek:

> Martin,
> 
> The "kfk: async disk IO" seems to be linked to the io_submit system call.
> You could check your number of async io processes.
> 
> But don't look at the number of occurrences to determine how "heavy" an event 
> is, look at the time spend. There is no relation between number of 
> occurrences and time spend.
> 
> 
> Regards,
> 
> 
> Freek D'Hooge
> Uptime
> Oracle Database Administrator
> email: freek.dhooge@xxxxxxxxx
> tel +32(0)3 451 23 82
> http://www.uptime.be
> disclaimer: www.uptime.be/disclaimer
> --
> From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On 
> Behalf Of Martin Berger
> Sent: dinsdag 7 december 2010 9:50
> To: Oracle-L Freelists
> Subject: what is "kfk: async disk IO"?
> 
> Hi,
> 
> can anyone please hint me to some information about  
> kfk: async disk IO ?
> 
> A little query on v$sessions gave me 
> USERNAME                     EVENT                                            
>     COUNT(*)
> ------------------------------ 
> -------------------------------------------------- ----------
> APPS                         ges message buffer allocation                    
>           98
> APPS                         CSS operation: action                            
>            2
> APPS                         Streams AQ: waiting for messages in the queue    
>            9
> SYS                          SQL*Net message to client                        
>            1
> APPS                         SQL*Net message from client                      
>          147
> APPS                         kfk: async disk IO                               
>         1646
> 
> as kfk: async disk IO is the bigest contributor, I'd like to investigate a 
> little bit.
> 
> for the records: 11.2.0.1 - 2 node RAC - RedHat 5.4 Linux 64-bit. (yes, it's 
> EBS - but don't ask me the exact pach level, please - I assume 11.5.10???) 
> 
> thnx 
>  Martin 

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