EMC Backup and Recovery for Oracle 11g OLTP Enabled by EMC ...

Chapter 3: Storage Design
ASM diskgroups
The database was built using four distinct ASM diskgroups:
• The Data diskgroup contained all datafiles and the first control file.
• The Online Redo diskgroup contained online redo logs for the database and
a second control file. Ordinarily, Oracle’s best practice recommendation is
for the redo logs files to be placed in the same diskgroup as all the database
files (the Data diskgroup in this example). However, it is necessary to
separate the online redo logs from the data diskgroup when planning to do
recovery from split mirror snap copies since the current redo log files cannot
be used to recover the cloned database.
• The Flash Recovery diskgroup contained the archive logs.
• The Temp diskgroup contained tempfiles.
ASM data area
MetaLUNs were chosen for ease of management and future scalability. As the data
grows, and consequently the number of ASM disks increases, ASM will have an
inherent overhead managing a large number of disks. Therefore, metaLUNs were
selected to allow the CLARiiON to manage request queues for large number of
LUNs.
For the Data diskgroup, four striped metaLUNs was created, each containing four
members. The selection of members for each metaLUN was chosen to ensure that
each member resided on a different back-end bus to ensure maximum throughput.
The starting LUN for each metaLUN were also carefully selected to avoid all the
metaLUNs starting on the same RAID group. This selection criterion was to avoid
starting all the ASM disks on the same set of spindles, and alternating the metaLUN
members to balance the LUN residence. This methodology was used to ensure that
ASM parallel chunk IOs would not hit the same spindles at the same time within the
metaLUNs when, or if, Oracle performed a parallel table scan.
EMC Backup and Recovery for Oracle 11g OLTP Enabled by EMC CLARiiON, EMC Data Domain, EMC NetWorker,
and Oracle Recovery Manager using NFS Proven Solution Guide
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