Slide 1 : Oracle Database 10g
Automatic Storage ManagementConcepts and Administration Greg Dmello
Advanced Customer Service
Oracle Corporation
Agenda : Agenda Why ASM?
What is ASM?
ASM Concepts
Mirroring Feature of ASM
Where DBAs Spend Their Time : Where DBAs Spend Their Time Ongoing System Management 55% Installation 6% Others
15% DataLoading 6%
The DBA Storage Challenges : The DBA Storage Challenges Databases are rapidly growing in size
DBAs have to manage thousands of data files
Decreasing windows of scheduled downtime
Storage resources involve many organizations
Database Admin
Systems Admin
Storage Admin
Network Admin
Management of database storage is increasing in complexity and cost
Oracle Automatic Storage Management (ASM) : Oracle Automatic Storage Management (ASM) New capability in Oracle 10g Database
Provides a vertical integration of the file system and volume manager for Oracle database files
Spreads database files across all available storage for optimal performance and resource utilization
Enables simple and non-intrusive resource allocation and provides automatic rebalancing
The Operational Stack : Automatic
Storage
Management The Operational Stack Disks Logical Vol File System Files Tablespace Tables Disk Group Logical Vol File System File Names Tablespace Tables Before ASM ASM Networked Storage
(SAN, NAS, DAS)
Traditional vs ASM – Tune I/O : Traditional vs ASM – Tune I/O Daily monitor I/O performance
Discover hot spots
Figure out how to remove hot spots
Move data to new files
Rename files in database
Verify that hot spot is gone This space intentionally left blank
Traditional vs ASM – Manage Space : Traditional vs ASM – Manage Space Daily monitor storage utilization
Discover fragmentation
Figure out how to remove fragmentation
Move data to new files
Rename files in database
Verify that fragmentation is gone This space intentionally left blank
Traditional vs ASM - Setup : Traditional vs ASM - Setup Determine required storage capacity
Install Volume Manager, File System
Architect data layout to avoid hot spot
Create logical volumes
Create file systems
Install database
Create database Determine required storage capacity
Install ASM
Create Disk Groups
Install database
Create database
ASM Architecture : ASM Architecture Pool of Storage ASM Instance Server Non–RAC
Database Oracle
DB Instance Disk Group
ASM Architecture : ASM Architecture Clustered
Pool of Storage ASM Instance ASM Instance Clustered
Servers RAC
Database Oracle
DB Instance Oracle
DB Instance Disk Group
ASM Concepts : ASM Concepts ASM Instance
ASM Disk Groups
ASM Failure Groups
ASM Disks
ASM Files
ASM File Templates
ASM Instance : ASM Instance Oracle instance to manage the metadata for disk groups (uses ~100 MB memory)
All metadata modifications are done by an ASM instance to isolate failures
Database instances connect to ASM instance to create, delete, resize, open, or close files
Database instances read/write directly to disk
One ASM instance per node in a cluster
ASM instance failure kills attached database instances
ASM Disk Groups : ASM Disk Groups Disk Group A pool of disks managed as a logical unit
ASM Disk Groups : ASM Disk Groups Disk Group A pool of disks managed as a logical unit
Divides total disk space into uniform sized megabyte units
ASM Disk Groups : ASM Disk Groups Disk Group A pool of disks managed as a logical unit
Divides total disk space into uniform sized megabyte units
ASM spreads each Oracle file evenly across all disks in a disk group
Disk Groups & Failure Groups : Disk Groups & Failure Groups Failure Group 1 Failure Group 2 Controller 1 Controller 2 Disk Group Storage resources organized into Disk Groups and Failure Groups
A Disk Group is a collection of disks managed as a logical unit in which ASM files are stored
Disk Groups assigned by DBAs
A Failure Group is a set of disks sharing a common resource whose failure needs to be tolerated
Redundant copies of an extent are stored in separate Failure Groups
Failure Groups assigned by DBAs or automatically by ASM
ASM Disks : ASM Disks Unit of persistent storage for a disk group
Accessed through normal OS interfaces
Oracle must have read/write access
Must be accessible to all nodes of a cluster
May have different names on different nodes
Cannot be a local file system file
Must not include partition table
Unit that fails if using redundancy
Disks in a disk group are the same percent full
ASM Files : ASM Files Mechanism to interact with higher code layers
File name starts with ‘+’, for example +DATA/mydb/datafile/system.256.1
All blocked files read and written by Oracle such as datafiles, logs, backups, controlfile …
Only files with Oracle file types
No ASCII files like trace files or alert logs
No executables
ASM files : ASM files ASM filenames can be used for files created by the database
ASM provides file system style directories
+group1/dir2/file3
Symbolic links can also be created using aliases
ASM File Templates : ASM File Templates Allow additional control for file attributes
Mirroring (Normal redundancy only)
2-way
None
Coarse (1MB) or Fine-grained (8x128k) striping
Traditional vs ASM – Add Disk : Traditional vs ASM – Add Disk Add Disk to OS
Create volume(s) with Volume Manager
Create File System over volume
Figure out data to move to new disk
Move data to new files
Rename files in database
Re-tune I/O Add Disk to OS
Issue the Add Disk command
Adding a Disk with ASM : Adding a Disk with ASM Disk Group DBA issues the request to add a disk to the existing disk group
ASM Dynamic Rebalancing : ASM Dynamic Rebalancing Disk Group Automatic online rebalance whenever storage configuration changes
ASM Dynamic Rebalancing : ASM Dynamic Rebalancing Automatic online rebalance whenever storage configuration changes
Only move data proportional to storage added Disk Group
Traditional vs ASM – Remove Disk : Traditional vs ASM – Remove Disk List all data that is on disk
Choose existing filesystem to hold data from dropped disk
Move data to new files
Rename files in database
Remove disk from OS
Re-tune I/O Issue drop disk command
Remove the disk from OS when Oracle says it is done
Traditional vs ASM – Migrate Data : Traditional vs ASM – Migrate Data Add new disks to OS
Figure out new location on other disks
Create volume(s) with Volume Manager
Create new FS
Move data to new files
Rename files in database
Remove old disks from OS
Re-tune I/O Add new disks to OS
Issue Add disk command for new disks
Issue Drop Disk command for old disks
Remove old disks from OS when Oracle says it is done
Data Distribution : Data Distribution Automatic Storage Management Extends SAME
Allows dynamic online Storage reconfiguration
Efficient relocation of data during rebalance
Eliminate manual I/O tuning in all storage configurations
ASM Mirroring : ASM Mirroring 3 choices for disk group redundancy
External: defers to hardware mirroring
Normal: 2-way mirroring
High: 3-way mirroring
Redundancy specified at disk group creation
ASM Mirroring : ASM Mirroring Mirror at extent level
Mix primary & mirror extents on each disk
ASM Mirroring : ASM Mirroring Mirror at extent level
Mix primary & mirror extents on each disk
ASM Mirroring : ASM Mirroring No hot spare disk required
Just spare capacity
Failed disk load spread among survivors
Maintains balanced I/O load
ASM Benefits : ASM Benefits Simplified management interface for storage resources
Increases the productivity of the DBA
Eliminates manual I/O performance tuning tasks
Virtualizes the storage to a set of disk groups
Provides mainframe class performance at lower cost
Business Benefits of ASM : Business Benefits of ASM Increases Uptime
Database is always available
Automated file naming and mgmt ? less errors
Online changes to storage resources (Add disks, remove disks and migrate to new storage)
Reduces Cost of Management
Automates database layout and file naming
Obsoletes manual I/O tuning
Manage more databases with same personnel
Optimizes Resource Utilization
Higher use of existing hardware investment
Increased performance (DBs and DBAs)
ASM Striping : ASM Striping
Sample Default Templates : Sample Default Templates
Backup with ASM : Backup with ASM RMAN is used for backing up database working on ASM.
Storage copy works with ASM.
dd drive is no longer an option.
RAC and ASM : RAC and ASM 1 ASM instance per node ASM RDBMS ASM RDBMS
ASM Views : ASM Views V$asm_disk
V$asm_diskgroup
V$asm_file
V$asm_alias
V$asm_template
V$asm_operation
V$asm_client
Contact Information : Contact Information Greg.b.dmello@oracle.com
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