Oracle Database 11 g - Online Public Access Catalog

CHAPTER 9■ ■ ■Storage ManagementWith Oracle Database 11g, numerous improvements have been incorporated into automatedstorage management (ASM) to provide higher availability, easier manageability, andbetter performance to the database community. This chapter will address the pertinent newASM features introduced in Oracle Database 11g:• Rolling upgrades• ASM fast disk resynchronization• ASM preferred read failure groups• ASM diskgroup attributes for backward compatibility• Separation of the DBA and SA roles via the sysasm role• New manageability options for the check, mount, and drop commands• A copy command to copy files between diskgroups, across ASM instances, and betweenASM and the operating system• ASM extensions such as diskgroup metadata backup and restore and block repairLater in the chapter, the topic will change to another highly anticipated Oracle Database11g feature called Direct NFS. RAC and non-RAC customers who leverage NFS today on filerscan take advantage of Oracle’s new Direct NFS. Direct NFS provides simplicity and performancefor database implementations on network-attached storage (NAS). Customers have opted forNFS solutions over block devices for simplicity and lower cost, and Direct NFS makes NFSimplementations even simpler and faster.Automated Storage ManagementOracle Database 10g introduced ASM as an alternative to the file system for storing databasefiles. ASM challenges file system management as we know it today by providing an integratedfile system and volume manager in the database kernel. Many DBAs ask the same question:What does ASM buy me? There are many reasons why DBAs, SAs, and SAN administratorsshould consider ASM. Here are the most important reasons:• Raw device performance• Logical volume management361