ORA-27090 error resolution instance

ORA-27090 error resolution instance

The recent alert Log encountered an error message for the ORA-27090 with the error prompt Unable to reserve kernel resources for asynchronous disk I/O. According to this prompt, It is a kernel parameter problem related to asynchronous I/O. The following describes and solves the problem.

1. Fault error information
Wed Sep 10 09:58:17 CST 2014
Errors in file/u01/app/Oracle/admin/orclls/bdump/orclls_p000_4701_trc:
ORA-27090: Unable to reserve kernel resources for asynchronous disk I/O
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
Additional information: 128
Additional information: 65536
Wed Sep 10 09:58:17 CST 2014
Errors in file/u01/app/oracle/admin/orclls/bdump/orclls_p002_47024.trc:
ORA-27090: Unable to reserve kernel resources for asynchronous disk I/O
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
Additional information: 128
Additional information: 65536

2. Fault Analysis
# Calling oerr does not obtain valuable information, as shown below:
SUSE11b: oracle: orcl102> oerr ora 27090
27090,000 00, "Unable to reserve kernel resources for asynchronous disk I/O"
// * Cause: The system call to reserve kernel resources for asynchronous I/O
// Has failed.
// * Action: Check errno

# View the trace file. Note that the current database version is 10.2.0.5 and the OS is suse 11 sp3.
Suse11a: oracle: orcl101> more/u01/app/oracle/admin/orclls/bdump/orclls_p002_47024.trc
/U01/app/oracle/admin/orclls/bdump/orclls_p002_47024.trc
Oracle Database 10g Enterprise Edition Release 10.2.0.5.0-64bit Production
With the Partitioning, Real Application Clusters, OLAP, Data Mining
And Real Application Testing options
ORACLE_HOME =/u01/app/oracle/product/10.2/db_1
System name: Linux
Node name: suse11a
Release: 3.0.76-0.11-default
Version: #1 SMP Fri Jun 14 08:21:43 UTC 2013 (ccab990)
Machine: x86_64
Instance name: orclls
Redo thread mounted by this instance: 1
Oracle process number: 35
Unix process pid: 47024, image: oracle @ suse11a (P002)

* ** Service name :() 09:58:17. 159
* ** Session id: (1072.1) 09:58:17. 159
* ** 09:58:17. 159
KCRP: blocks claimed = 0, eliminated = 0
----- Recovery Hash Table Statistics ---------
Hash table buckets = 32768
Longest hash chain = 0
Average hash chain = 0/0 = 0.0
Max compares per lookup = 0
Avg compares per lookup = 0/0 = 0.0
----------------------------------------------
ORA-27090: Unable to reserve kernel resources for asynchronous disk I/O
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
Additional information: 128
Additional information: 65536
----- Recovery Hash Table Statistics ---------
Hash table buckets = 32768
Longest hash chain = 0
Average hash chain = 0/0 = 0.0
Max compares per lookup = 0
Avg compares per lookup = 0/0 = 0.0
----------------------------------------------
# No valuable information is obtained from the trace file.

3. troubleshooting
# According to the ORA-27090: MESSAGE 27090 not found; (Document ID 579108.1), we modify the Kernel Parameter fs. aio-max-nr
# Because the database is in the RAC environment, two nodes are adjusted at the same time. The following figure shows the adjusted situation.
Suse11a :~ # Grep max-nr/etc/sysctl. conf
# Fs. aio-max-nr = 1048576
Fs. aio-max-nr = 3145728

Suse11b :~ # Grep max-nr/etc/sysctl. conf
# Aio-max-nr = 1048576
Fs. aio-max-nr = 3145728

Suse11a :~ # Sysctl-p
Suse11b :~ # Sysctl-p

# You can use cluvy to verify the configuration.
# Observe the alert Log in a few days and no such errors are found.

Check: Kernel parameter for "aio-max-nr"
Node Name Current Configured Required Status Comment
----------------------------------------------------------------------------
Suse11a 3145728 3145728 1048576 passed
Suse11b 3145728 3145728 1048576 passed
Result: Kernel parameter check passed for "aio-max-nr"

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