Release Notes

Optimize an SC Series array for an Oracle data warehouse
21 Optimizing Dell EMC SC Series Storage for Oracle OLAP Processing | 2009-M-BP-O
• Snapshots allow fast recovery and improve RTO and RPO. Data from snapshots are immediately
available through view volumes.
• An instant backup should be created before major upgrades or changes in the data warehouse.
Considerations for planning snapshot schedules:
• Snapshots can be taken on a schedule or on-demand.
• Schedule snapshots based on backup policy and RPO. SC Series storage allows a schedule as
frequent as every 5 minutes.
• Schedule based on the data ingestion cycle. Take a snapshot after each mass data load. This allows
Data Progression to optimize the frozen pages by moving to different RAID levels and storage tiers.
• Set an expiration policy to automatically reclaim storage space from obsolete snapshots.
• Multiple schedules can be attached to the same snapshot profile. It is highly recommended to have at
least one daily snapshot scheduled for every SC Series volume.
When a database spans across multiple storage volumes like the example shown in Figure 2, the storage
volumes of the same database must be assigned to the same snapshot profile and the consistent method
must be chosen for the profile. Otherwise, Oracle might not be able to recover from a multi-volume snapshot.
This consistency group feature allows taking a database-consistent snapshot that spans across multiple
volumes. On the Oracle side, use ALTER DATABASE BEGIN BACKUP and END BACKUP before and after
the snapshot is taken. Similarly, a consistency group should be configured for multi-volume LVM.
To access or restore data from a snapshot, a view volume is created and mounted with full read-write access
on any recovery system in DSM. A view volume shares the frozen pages with the parent volume but data
written to the view volume is tracked separately and consumes real storage space. A view volume is treated
like a regular volume in that it has its own volume attributes and changes to the view volume does not affect
its parent volume.
3.6 Sizing considerations
When sizing an SC Series array for a data warehouse, the goal is to maximize I/O bandwidth by having
enough physical disks in each tier and channels accessing the data. It is important to work closely with your
Dell EMC account team to collect and understand the information described in the following sections.
3.6.1 Collect and measure performance statistics
Performance expectations must be defined by quantifiable measurements and clearly communicated to all
teams involved, including the Dell EMC team, so that they can properly size the SC Series array to meet the
objectives. Collect performance statistics in an existing environment that has similar workload and activities to
the final environment is strongly preferred.
Some operating systems provide native tools that collect basic IOPS information. For example, on Linux, sar
and iostat come pre-installed on the system. Other free utilities like atop and collectl are similar to sar but
have additional features. On Microsoft Windows, Performance Monitor is readily available. Dell EMC also
offers a free tool, the Dell Performance Analysis Collection Kit (DPACK), to assist in collecting and
analyzing system and I/O performance data. For information on DPACK, see the DPACK FAQ or contact the
Dell EMC team.
For an Oracle database, the utilities used most are statspack and AWR. AWR is preferred to the older
statspack, but either one can provide abundant performance statistics of a database.