Dell Compellent Series 40 - Manual (Page 5)

Cost and Performance benefits of Dell™ Compellent™ Automated Tiered Storage for Oracle® OLAP
Workloads
5
Executive summary
Data growth in the Enterprise world is enormous. In the traditional system, to achieve high
performance needs, all the data must reside in the high performing disks irrespective of the access
pattern. However, all the data residing in these disks may not be accessible all the time as a result
high performing disks are used inefficiently. To avoid this, many storage vendors have adopted a
concept called tiering . Tiered storage consists of different disks that differ in cost, performance, and
capacity. Tiered storage enables placing the data in the right tier based on usage pattern,
performance, and cost requirements but it requires a manual intervention to move and reformat data.
In Dell™ Compellent™ storage systems, this process of tiering is automatic. You get the benefit of
automatic tiering by enabling data progression, which automatically moves data to the right place at
the right time based on usage pattern and performance needs. This paper emphasizes Dell Compellent
Automatic Tiering and provides the cost and performance benefits that are achieved using the
automatic storage tiering features like Fast Track, Data Instant Replay, and Data Progression for
Oracle® database OLAP workload.
Introduction
Storage tiering is an important strategy for optimizing storage expenditures, which helps organizations
achieve lower storage costs by storing less important data on less costly disks. However, the hidden
costs of data classification and the manual movement of data between tiers, along with the purchase
and integration of multiple point products, quickly eliminate any potential savings. Without an
intelligent and automated solution, the benefits of tiered storage are immediately outweighed by the
resulting cost and management burden. Because Compellent Storage Center operates at the block
level, Dell Compellent storage has the intelligence to move infrequently accessed data to lower tier
disks automatically. With Compellent Data Progression enabled, you can take advantage of a complete
automated tier storage solution and eliminate the need for manual data classification and transfer.
Oracle Database workloads are classified as online transaction processing (OLTP) or online application
processing (OLAP) or a mix of both workloads. For a typical OLTP workload, only a small set of data is
active, which must be placed in a high performing storage tier. In an OLAP database, most of the data
is accessed only once in a while. This OLAP data is placed in high-capacity and low-cost tiers. In
addition, in an OLAP work load, the amount of data that gets written is small, so you can get a cost
benefit by placing data in cost efficient RAID5 storage.
This paper outlines how each of the Compellent automatic storage tiering features helps the Oracle
Database OLAP workload to achieve better usage:
Fast Track Fast Track places frequently accessed data on the outermost sector of the drives
to improve the performance.
Data Instant
Replay Data Instant Replay moves read-only data from RAID 10 to RAID 5 within the same
tier, which maintains the same read performance and frees up space on the RAID
level.
Data Progression Data Progression deals with moving infrequently accessed blocks of data to a
lower storage tier and RAID level, or to a different RAID level within the same
tier. Whether data is moved to a new tier or RAID level, the migration frees up
space on the higher tier or RAID level.