Symptoms
ORA-01115: IO error reading block from file 393 (block# 2959)
ORA-01110: data file 393: '/u01/proddata/data/ard01.dbf'
ORA-27091: skgfqio: unable to queue I/O
ORA-27027: 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.
Solutions
Increase maxreqs from 8192 to 12288.
Steps:
1. run aioo -a command to double check current setting for aioo device
2. run aioo -o maxreqs=12288 to set maxreqs dynamically
3. chdev -l aioo -a maxreqs=12288 to set the value of maxreqs permanently for next reboot
4. run aioo -a to confirm change
5. restart oracle
Metalink Note:559697.1
1 comment:
> chdev -l aioo -a maxreqs=12288
The correct form is:
chdev -Pl aio0 -a maxreqs=12288
aio0 is the device name and you need the -P flag as the device is busy, so cannot be changed while in use
NB: AIX 6.1 scales async I/O dynamically.
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