Cluster file systems versus raw devices in Oracle RAC

From: Antonio Belloni <toni_belloni_at_yahoo.com.br>
Date: 2005-12-26 19:02:32
Message-id: 20051226180232.14708.qmail@web34711.mail.mud.yahoo.com

Hi,

Does anyone using cluster file systems in a RAC 10gR2 installation, specifically IBM’s GPFS?

I’ve visited a company that is running RAC 10gR2 in AIX over raw devices. Why someone would choose to use raw devices , with all the problems to administer , when all the modern file systems are so powerful? Is there any issues when using cluster file systems + RAC? Is there considerable performance benefits when using raw devices with RAC ?

I´ve always used Oracle stand alone instances over file systems (since version 7) , and performance was always very good. I´ve tested raw devices almost 10 years ago , and even in that time (the hardware today is much better - SAN , 15K rpm disks , huge caches - and the file systems software today is much better) the cost to administer it does not compensate the benefits (only 5% more faster than file systems in Oracle 7).

So , as I didn't see a line in the Oracle RAC documentation saying that RAC only works over raw devices and besides any limitations imposed by RAC , why use raw devices nowadays ?

Regards,
Antonio Belloni                                   

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Received on Mon Dec 26 2005 - 19:02:32 CST