Introduction to Automatic Storage Management of OracleASM

ASM is called AutomatedStorageManagement, which is called Automatic Storage Management. It is a new feature launched by Oracle of Oracle10g. This is what Oracle provides

ASM is called Automatic Storage Management (Automatic Storage Management). It is a new feature launched by Oracle 10 Gb. This is what Oracle provides

1. What is ASM?

ASM is called Automatic Storage Management (Automatic Storage Management). It is a new feature launched by Oracle 10 Gb. This is a volume manager provided by Oracle to replace the LVM provided by the operating system. It not only supports single-instance configuration, but also supports multi-instance configuration such as RAC. It will bring great convenience to the Oracle database administrator. ASM can automatically manage the disk groups and provide data redundancy and optimization. Especially for enterprise-level large database administrators, administrators can be freed from the trivial daily tasks of managing hundreds of data files to process other and more important transactions.

Before the Oracle 10 GB version, managing hundreds of thousands of data files in a large database was neither technical nor boring for database administrators, this requires the database administrator to be familiar with the LVM related knowledge of the system and perform related system operations such as disk specification and LV strip. The use of Automatic Storage Management will greatly reduce the workload in this regard. The database administrator only needs to manage a few disk groups. A disk group is a logical unit managed by ASM and consists of a group of disk devices. We can define a disk group as the default disk group for the database. Oracle automatically manages the storage, including creating and deleting data files. Oracle automatically associates these files with a suitable database object, so that we only need to provide the object name when managing these objects, instead of providing the detailed file name as before.

ASM provides many useful storage technologies, such as RAID and LVM (logical volume management. Like these technologies, ASM allows you to create a separate disk group on a group of Independent Disks. In this way, I/O balancing is achieved for a single disk group. At the same time, ASM also implements strip and Disk Mirroring to improve I/O performance and data reliability. Unlike RAID or LVM, ASM is a file-level implementation of strip and image. Such implementation gives users great freedom of choice, you can configure different storage attributes for different files in the same disk group to implement different storage methods.

What are new features of ASM in 2 11G?

2.1 Fast re-synchronization (ASM Fast Mirror Resync)

When a short DISK path is faulty, it takes a lot of time to restore the remainder of the asm disk group, especially when such a restoration operation requires the entire disk group to be redeployed. The new feature of ASM fast disk re-synchronization can significantly reduce the time required to re-synchronize a bad disk. When you replace the bad disk, ASM can quickly synchronize the extent of the ASM disk.

2.2 ASM rolling upgrade

In ORACLE11g and later versions, you can set the ASM cluster to "rolling upgrade" mode, allowing different versions of ASM nodes to work together. In the rolling upgrade mode, each node can be upgraded or patched independently without affecting the database usage. This greatly improves the normal running time of the database. Note that you can only perform "rolling upgrade" for ORACLE11g and later versions. In other words, you cannot use this function to upgrade ORACLE10g databases to 11G.