11g Automatic Storage Management (ASM) Enhancements

Before looking at the 11g New Features for ASM in this chapter, take a quick look at the history of ASM and give a short outlook on the possible new features of upcoming releases. Automatic Storage management is certainly one of Oracle's most important projects. Oracle puts a lot of marketing energy into the promotion of ASM. For example, they included a two node RAC license into the standard edition license of the database software as of version 10gR1, but only in combination with the use of ASM for the shared storage.

ASM is one of Oracle's key Grid Computing Features next to RAC, STREAMS and GRID CONTROL. It is a logical volume manager not only for RAC, it also represents Oracle's solution for the SAME (stripe and mirror everything) demand for database storage. ASM offers a good means for storage consolidation.

It is part of Oracle's strategy to integrate more and more operation system functionalities into the database. Some day Oracle will probably be an OS itself.
Today there is an Oracle proprietary logical volume manager (ASM) and Oracle can copy files on the same host to and from other hosts, which is implemented by the 10gR1 built in package DBMS_FILE_TRANSFER. This package was improved in 10gR2 to support OS to ASM and ASM to OS file transfer. In 10gR1, only ASM to ASM and OS to OS were possible.

Another 10gR2 feature for shifting large amounts of data around between databases is DBMS_STREAMS_TABLESPACE_ADM, a package which can be used for cloning tablespaces and tablespace versioning.

Furthermore, Oracle version 10gR2 Oracle ships its own media management server called Oracle Secure Backup (OSB) which can not only backup Oracle files but entire file systems, NAS storage as well as SAN. It can handle tape libraries and barcode readers and is strongly integrated with Recovery Manager (RMAN). Oracle Corporation puts a lot of effort into the development of the ASM functionality and it is still undergoing change. This will most likely continue in the next future releases.

In Oracle 10g as well as in 11g, it is only possible to store files which belong directly to the database, such as datafiles, online redo log files and controlfiles. It is also possible to store spfiles, export data pump dump file sets and everything which has to do with backup and recovery, namely RMAN backupsets, datafile image copies and archived redo log files.

What Oracle is still working on with maximum effort is the possibility to store binary files; for example, an ORACLE_HOME, in ASM storage. It is even thinkable that any kind of file could be stored in ASM storage someday. Right now, DBMS_FILE_TRANSFER can be used to move files into and out of the ASM storage as well as from one ASM disk group to another one. It is also possible to simply use the FTP API of Oracle version 10gR2 called ASM FTP which utilizes the XML DB virtual folder functionality to move files into and out of ASM storage. 

In future releases it will probably also be possible to use ASM disk groups to hold the Voting Disk and the Oracle Cluster Registry (OCR). In theory, it is already possible today - ASM could hold an OCR or a voting disk, but the problem here is the chicken-egg-story; in order to store the voting disk into ASM, there needs to be a clustered ASM which again would need the clusterware in place before it has been installed. Next to be covered are the ASM New Features in Oracle version 11gR1.

The first ?feature? to be discussed is the new volume for ASM in the Online Documentation.