Oracle/HP Best Practices Guide for HP IO Accelerators

Redundancy architectures 9
This command mirrors across three devices (/dev/fioa[g,h,i]) to create the LOGDG disk group.
ASM SQL > CREATE DISKGROUP LOGDG HIGH REDUNDANCY
FAILGROUP failure_group_1 DISK
'/dev/fiog' NAME diska1,
FAILGROUP failure_group_2 DISK
'/dev/fioh' NAME diskb1,
FAILGROUP failure_group_2 DISK
'/dev/fioi' NAME diskc1,
ASM mirroring with a read-preferred device
ASM enables you to select a device in a mirrored disk group that handles all the reads and receives all
the writes. This enables the other devices in the group to receive only the writes. Using this solution, the IO
Accelerator can be paired in a mirror with traditional storage and maintain its significant performance
advantage. However, log commit/sync write latency is still as slow as the slowest device in the pair.
To configure this feature, set the ASM_PREFERRED_READ_FAILURE_GROUPS initialization parameter in
the ASM instance to specify a list of failure group names as preferred read disks. Set the parameter
where diskgroup is the name of the disk group and failuregroup is the name of the failure group,
separating these variables with a period.
ASM_PREFERRED_READ_FAILURE_GROUPS = diskgroup.failuregroup,...
For example, to enable read preferred mode on DATADG.failure_group_1 use the following
command:
ASM_PREFERRED_READ_FAILURE_GROUPS=DATADG.failure_group_1
The DATADG disk group could then be configured to include all IO Accelerators in Failure_group_1
and all storage devices that are not IO Accelerators in Failure_group_2 as follows:
ASM SQL > CREATE DISKGROUP DATADG NORMAL REDUNDANCY
FAILGROUP failure_group_1 DISK
'/dev/fioa' NAME diska1,
'/dev/fiob' NAME diska2,
FAILGROUP failure_group_2 DISK
'/dev/sdd' NAME diskb1,
'/dev/sdc' NAME diskb2,
In this example, it is assumed that each /dev/sd* device is as large as each /dev/fio* device.
For more information on ASM, see the Oracle website (http://www.oracle-
base.com/articles/10g/AutomaticStorageManagement10g.php ).
Using data guard
Oracle Data Guard provides the management, monitoring, and automation software to create and
maintain one or more standby databases. These features help to protect Oracle data from failures,
disasters, human error, and data corruption.