Release Notes

Optimize an SC Series array for an Oracle data warehouse
11 Optimizing Dell EMC SC Series Storage for Oracle OLAP Processing | 2009-M-BP-O
3.3.1 Oracle ASM
Dell EMC and Oracle recommend using Oracle Automatic Storage Management (ASM) to manage SC Series
volumes for the database and clusterware. This section reviews the general guidelines and additional
considerations for a data warehouse.
ASM guidelines:
• Configure a separate diskgroup for the Oracle clusterware.
• A data warehouse can span across multiple diskgroups. Arrange different data types into separate
disk groups where appropriate storage profiles and data reduction features can be applied to
maximize storage efficiency and performance. See section 3.4 for further details.
• Make sure volumes in the same diskgroup have the same capacity and volume attributes such as
data reduction, volume cache and storage profile on a SC Series array.
• Use fewer but larger volumes to reduce the number of objects to be managed. SCOS supports up to
2,000 volumes in a single SC Series array and a maximum volume size of 500TB.
• Make sure each disk group contains even numbers of volumes to allow I/O distribution to both SC
Series controllers, hence, maximizing the performance and I/O bandwidth for the data warehouse.
• Ensure that diskgroups are mounted and used by a data warehouse exclusively and not shared with
other databases. This simplifies using array-based snapshots for backup and recovery.
• In order to take an array-based snapshot on a multi-volume Oracle data warehouse, make sure that
all volumes belonging to the same data warehouse are snapped together. This can be achieved by
creating a consistent snapshot profile and assigning it to the volumes. In Figure 2, for example,
volumes in +SYSTEMDG, +DATA1DG, +DATA2DG, and +FRADG have the same consistent
snapshot profile.
• Keep the total number of ASM disks for a data warehouse (+SYSTEMDG, +DATA1DG, +DATA2DG
and +FRADG) below the snapshot consistency group limits. The limits vary across SC Series array
models and SCOS versions. For example, an SC5020 array with SCOS 7.2 supports 50 volumes per
consistency group, while an SC7020 with SCOS 7.2 supports 100 volumes per consistency group.
The limits are documented in the SCOS release notes (found on Dell.com/support) under the
Scalability Guidelines. See section 3.5 for more details on snapshots and consistency groups.
• While ASM can provide software-level mirroring, it is not necessary because data protection has
already been provided by the built-in SC Series multi-RAID levels. Use External Redundancy for
ASM disk groups to enable substantial storage savings on a large data warehouse. This also reduces
overall IOPS from ASM and results in better I/O performance.
For more information on Oracle ASM best practices with SC Series arrays, see the document, Dell SC Series
Storage with Oracle ASM Best Practices.