Re: Database Problem Or system

Posted by ErmanArslansOracleBlog on Mar 10, 2017; 4:51pm
URL: http://erman-arslan-s-oracle-forum.124.s1.nabble.com/Database-Problem-Or-system-tp2334p2335.html

Is the OS IBM AIX?

If it is so, following is your action plan:
( we have encountered earlier in our AIX customers...)


Applies to:Oracle Database - Enterprise Edition - Version 9.2.0.8 and later
IBM AIX on POWER Systems (64-bit)
***Checked for relevance on 16-Feb-2011***

IBM AIX Based Systems (64-bit)

Symptoms

After patching the OS with Patch IBM Technology Level 6 (5300-06) or Level 7 (5300-07), the application log started reporting the following errors:

ORA-01115: IO error reading block from file <file id> (block # <block number>)
ORA-01110: data file <file id>: <file name> 
ORA-27091: skgfqio: unable to queue I/O
ORA-27072: skgfdisp: I/O error
IBM AIX RISC System/6000 Error: 5: I/O error

- The errors are not reported in the alert log file.
- Running dbv against datafiles from the error messages shows no errors.
- All the mandatory OS patches are applied.
- Oracle patch for Bug 5496862 - IO READING PROBLEMS AFTER INSTALLING IBM TECHNOLOGY LEVEL 5 (5300-05) was installed before patching the OS.

Patch IBM Technology Level 6 (5300-06) or higher was applied to the OS.

The value of maxreqs (4096) was too low. This asynchronous I/O parameter specifies the maximum number of asynchronous I/O requests that can be outstanding at any one time and has as default value 4096.

Increase maxreqs to a value greater than or equal to 8192.

Steps:
1. run aioo -a command to double check current setting for aio0 device
2. run aioo -o maxreqs=<value> to set maxreqs dynamically
3. chdev -l aio0 -a maxreqs=<value> -P to set the value of maxreqs permanently for next reboot
4. run aioo -a to confirm change
5. restart oracle

NOTE: Values that fixed the errors: 8192, 16384 or 32768.