Low speed in RAW device vs. Lvm Fs

[Francesco_13]

Hi,
i have a database oracle RAC in two nodes Hp-cluster (9.2.0.5).
Front a low performance i have testing a simple dd. When Raw device it's involved i have low performance. The same file in a dd with LVM fs is 3 time more quickly.
It's normal this? Maybe that raw device would be faster that FS.
Thanks.
Best regards.
Francesco

[Zygmunt Krawczyk]

Hi Francesco,

don't worry about these results. dd on raw volume and on file system tests different performance factors. Oracle database on raw volumes has always better performance vs file system. I recommend reading the doc:

"Best practices for Oracle on HP-UX"
http://h21007.www2.hp.com/dspp/files/unprotected/database/HP3KOracle.ppt

Regards,
Zygmunt

[Francesco_13]

thanks