Difference between revisions of "Directio"
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* http://karlarao.tiddlyspot.com/ > DirectIO | * http://karlarao.tiddlyspot.com/ > DirectIO | ||
* https://blogs.oracle.com/apatoki/entry/ensuring_that_directio_is_active | * https://blogs.oracle.com/apatoki/entry/ensuring_that_directio_is_active | ||
| + | * http://www.pythian.com/news/22727/how-to-confirm-direct-io-is-getting-used-on-solaris/ | ||
* Note that ASM will use AIO & Direct IO automatically. | * Note that ASM will use AIO & Direct IO automatically. | ||
Latest revision as of 09:18, 31 July 2012
How To Verify Whether DIRECTIO is Being Used [ID 555601.1]
- Use directiostat from http://www.solarisinternals.com/si/tools/directiostat/index.php
or
$ ps -ef |grep _dbw $ truss -aefo /tmp/truss.out -p 2260
Look for the ioctl call made after the open of a datafile, typically this will look something like:
19483: ioctl(3, 0x2000664C, 0x00000001) = 0
The 3rd argument value of 1 is used for DIRECTIO_ON, and 0 would be seen if a call was made with DIRECTIO_OFF.
- This sample is for new sqlplus session.
truss -f -t open,ioctl -u ':directio' sqlplus "/ as sysdba"
References:
- http://karlarao.tiddlyspot.com/ > DirectIO
- https://blogs.oracle.com/apatoki/entry/ensuring_that_directio_is_active
- http://www.pythian.com/news/22727/how-to-confirm-direct-io-is-getting-used-on-solaris/
- Note that ASM will use AIO & Direct IO automatically.
- ASM Inherently Performs Asynchronous I/O Regardless of filesystemio_options Parameter [ID 751463.1]
- Init.ora Parameter "FILESYSTEMIO_OPTIONS" Reference Note [ID 120697.1]
- Pros and Cons of Using Direct I/O for Databases [ID 1005087.1]
