New Smart Tier for Oracle Gives DBAs Increased Control for Granular Data Placement

Dynamically moving files from one tier of storage to another has been a feature on the Veritas File System (VxFS) for some time. But to date Oracle DBAs have lacked this same level of data mobility and granular control when managing Oracle database tables. This is no longer the case.

Symantec's new Smart Tier for Oracle, a feature included in the Storage Foundation High Availability 5.1 Service Pack 1 (SP1), offers the granular control that Oracle DBAs need to easily move entire database tables or data within database tables where they need it without the risk and expense associated with existing techniques.

Prior to the release of Storage Foundation HA 5.1 SP1 Oracle DBAs had one of three choices for managing the placement of their Oracle database tables on different tiers of storage:

1. An entire database table is contained in a single file. Symantec's Dynamic Storage Tiering in VxFS affords some flexibility for DBAs to move an Oracle database from one tier of storage to another but the level of control is not very granular. Movement of a table from one tier to another could only occur if the entire table was contained in one file. However in cases where the table spanned multiple files, VxFS could not take action. Further, even if an entire table is contained in one file, moving an entire file from one tier of storage to another may be neither practical nor affordable.
2. Partition the Oracle database. Oracle database could be partitioned such that Oracle DBAs would put lower performing tables on one tier of storage and higher performing tables on another. However this functionality in Oracle required the purchase of an Oracle database partitioning license which was only available for enterprise Oracle deployments. This option did not give Oracle DBAs an effective means to manage the life cycle of the data so tables could be moved from one tier to another as application requirements changed.
3. Use the storage tiering functionality available on high end storage systems. This feature has received a lot of attention in recent years but there are still more questions than answers in terms of how well this feature works when high performance database tables are placed on this storage. Questions associated with this approach include, "What is the right amount of data to move?", "When is the right time to move the data?" and "What overhead does the storage system incur?" Perhaps the greatest concern that Oracle DBAs have is that they lose control of the tier of storage that their Oracle application data is being placed on and under what conditions.
   

It is these limitations associated with current host-based methods and the uncertainty associated with storage system based techniques that the new Smart Tier for Oracle feature included in the Storage Foundation HA 5.1 SP1 addresses. Smart Tier for Oracle provides Oracle DBAs with a higher degree of control to place Oracle database tables on the most appropriate tier of storage without the cost or uncertainty associated with these other techniques.

To accomplish this Symantec has enhanced its existing Smart Tier policies so that it no longer matters to SP1's new Smart Tier for Oracle whether the table is spread across multiple files or if it is partitioned as Smart Tier for Oracle can move the table to the most appropriate tier of storage based upon input from the DBA.

This additional control gives Oracle DBAs the ability to create an Oracle database table that spans multiple files or even multiple file systems. In this way, DBAs can move an extent or a series of extents to a different tier of storage.

This addresses two concerns.
 

• On one front, data within a table that is deemed inactive or infrequently accessed can be moved to a lower performing tier of storage.
  
• On the other, extents of data that are frequently accessed or hit by the application can be moved to an even higher performing tier of storage such as Solid State Drives (SSDs) without needing to move the entire table to this tier of disk.

To determine what data should be moved and when, the Oracle DBA can leverage existing Oracle tools to monitor the database's performance. Then as certain parts of the database "heat up" or are accessed more frequently resulting in performance bottlenecks, the DBA can move that data to a higher tier of storage. Conversely, as data "cools off" or is accessed less frequently, the DBA can then move that data to lower performing storage and free up the higher performing storage capacity.

The ready availability of SSDs and SATA disk drives in enterprise storage systems coupled with a continuing focus on controlling storage costs are prompting enterprises to look for more ways to manage the storage associated with their Oracle databases in the most efficient way possible.
 
The introduction of Smart Tier for Oracle in Storage Foundation HA 5.1 SP1 gives enterprises an important and economical new way to meet this objective. By enabling Oracle tables to span files or file systems while avoiding expensive Oracle licensing costs, Smart Tier for Oracle gives enterprises the flexibility to deliver the performance that their Oracle applications need while enabling Oracle DBAs to more effectively use the storage assets under their control.