Vijay Adik vadik@us - IBM
Vijay Adik vadik@us - IBM
Vijay Adik vadik@us - IBM
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41<br />
<strong>IBM</strong> Advanced Technical Support - Americas<br />
AIX Filesystems Mount options (Cont’d)<br />
�Direct IO (DIO) – introduced in AIX 4.3.<br />
• Data is transfered directly from the disk to the<br />
application buffer, bypassing the file buffer<br />
cache hence avoiding double caching<br />
(filesystem cache + Oracle SGA).<br />
• Emulates a raw-device implementation.<br />
�To mount a filesystem in DIO<br />
$ mount –o dio /data<br />
�Concurrent IO (CIO) – introduced with JFS2 in<br />
AIX 5.2 ML1<br />
• Implicit use of DIO.<br />
• No Inode locking : Multiple threads can<br />
perform reads and writes on the same file at<br />
the same time.<br />
• Performance achieved using CIO is<br />
comparable to raw-devices.<br />
�To mount a filesystem in CIO:<br />
$ mount –o cio /data<br />
© 2009 <strong>IBM</strong> Corporation<br />
Bench throughput over run duration – higher<br />
tps indicates better performance.<br />
April 17, 2009
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