Oracle's 10gR2 ASM with Standard Linux I/O in CentOS 4.1 environment

[dbaxps]

PLease, view:-

http://www.puschitz.com/TuningLinuxF...racleDatabases

Per Werner Puschitz:-

For Oracle 10g Release 2 in RHEL 4 it is not recommended to use raw devices but to use block devices instead. Raw I/O is still available in RHEL 4 but it is now a deprecated interface. In fact, raw I/O has been deprecated by the Linux community. It has been replaced by the O_DIRECT flag which can be used for opening block devices to bypass the OS cache. Unfortunately, Oracle Clusterware R2 OUI still requires raw devices or a Cluster File System.

By default, reading and writing to block devices are buffered I/Os. Oracle 10g R2 now automatically opens all block devices such as SCSI disks using the O_DIRECT flag, thus bypassing the OS cache. For example, when you create disk groups for ASM and you want to use the SCSI block devices /dev/sdb and /dev/sdc, you can simply set the Disk Discovery Path to "/dev/sdb, /dev/sdc" to create the ASM disk group. There is no need to create raw devices and to point the Disk Discovery Path to it.