Server Appliance Proposal

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Bare Bones ASMWhat Every DBA Needs to Know
Jay Caviness Sr. Systems Engineer McKesson
Provider Technologies

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Topics

• What is ASM?
• Using ASM
• Caveats and Issues
• New Features in 11gR2

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McKesson Provider Technologies

• Largest Healthcare IS Company
• Oracle Solutions Partner
• McKesson Clinicals Applications
• 17 Applications Suites
• Meds Manager
• ER
• Billing/Revenue Management
• Nursing
• NICU/PICU

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About Me

• Oracle DBA for 20 years
• Senior Engineering DBA and Oracle Infrastructure
  Architect for McKesson Provider Technologies
• Administered Oracle from v5.1 11g
• Beta team for 11gR2
• Oracle Certified Professional
• Known as the Grumpy DBA

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McKesson Horizon Clinicals and ASM

• Over 800 hospital deploy McKesson applications
• ASM deployed starting in late 2005 (10gR1)?
• As of today more than 475 hospitals run Oracle
  ASM
• - Most run Oracle RAC - over 700 clusters
• - Linux, HP/UX and IBM-AIX

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McKesson Horizon Clinicals Client

• Starting disk space per installation 400GB
• Growth 2030 year over year
• Retention requirements vary by HIPAA rules,
  typically 7-10 years

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• Automated Storage Management

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Why ASM

• Why choose ASM?
• Setup and Management
• Simplicity
• Scalability Performance
• Robust and Stable

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What is ASM?

• Replaces conventional file systems and volume
  managers
• Capacity on demand
• Add/drop disks online
• Automatic I/O load balancing
• Stripes data across disks to balance load
• Automatic mirroring
• Easy to set up and use
• Works with SAN, NAS or filesystems

Automatic Storage Management
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What ASM does do

• Stripe mirror data across multiple disks
• Reduces management overhead
• Provides 0, 2 or 3-way mirroring
• Can store almost all types of database related
  files

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What ASM does not do

• Not an I/O broker or controller I/O is still
  managed by the individual instances
• Not a database INSTANCE_TYPEasm
• Acts as the mediator and definer
• Not foolproof, luns can be removed out from under
  ASM!

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ASM - Setup

• Install in own Oracle Home
• Determine redundancy/mirroring
• Determine LUN/Disk size
• Partition devices
• Install ASM software and start the mini-cluster

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The mini-cluster

• The Oracle Cluster Synchronization Services
  Daemon is required for ASM even for a single
  (non-RAC) database
• Used for communication between ASM and database
  instances
• Root.sh will create an entry in /etc/inittab to
  respawn cssd

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ASMlib

• Defines disk/luns for use with ASM
• Only available on Linux
• service oracleasm
• /dev/oracleasm

------------------------------------ -----------
------------------------------ asm_diskgroups
string DGROUP1 asm_diskstri
ng string ORCLVOL
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initASM.ora

• Only one ASM instance per node
• .asm_diskgroupsDATA'
• .asm_diskstring'ORCL -- linux
• .asm_diskstring/dev/asm_disk -- unix
• .asm_diskstring/dev/c0t1d1 unix
• .asm_diskstring/dev/sda1
• .instance_type'asm'
• .processes500 - Set to minimum of 25 15
  number of databases uses ASM for storage

------------------------------------ -----------
------------------------------ asm_diskgroups
string DGROUP1 asm_diskstri
ng string ORCLVOL
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Diskgroups

• Diskgroups are the logical storage units for ASM
• One or more for all databases on a server or
  cluster
• Often, two diskgroups are created, one for
  tablespace and another for FRA
• Diskgroups may also be created by SAN speed
  (fast, middle, slow)

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Redundancy

• ASM supports three types of redundancy
• External no mirroring within ASM, all at the OS
  level
• Normal the default two way mirroring, each
  stripe is written to two extents
• High three way mirroring each stripe written
  to one primary and two mirrored extents

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Failgroups

• Failgroups cannot be removed without recreating
  the diskgroup.
• If one failgroup is lost or offline for a period
  of time, it will be re-synced when available
  again
• Fail groups should be across different
  controllers or SANs

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Tools to Manage ASM

• SQLPlus
• ASMCMD
• Grid Control / Database Control
• SRVCTL RAC only

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Basic ASM Commands

• Create a diskgroupCREATE DISKGROUP dgroup1 DISK
  orclvol001,orclvol002
• Drop a diskgroupDROP DISKGROUP dgroup1
• To drop a diskgroup which still contains data
• DROP DISKGROUP dgroup1 INCLUDING CONTENTS

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Basic ASM Commands

• Add luns to a diskgroup ALTER DISKGROUP dgroup1
  ADD DISK orclvol006
• Remove luns from a diskgroupALTER DISKGROUP
  dgroup1 REMOVE DISK vol006
• Do both at the same timeALTER DISKGROUP dgroup1
• ADD DISK
• 'ORCLVOL003','ORCLVOL004'
• DROP DISK
• 'VOL005'
• REBALANCE POWER 6

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Rebalancing

• Redistribution only occurs when adding or
  dropping disk
• Change the asm_power_limit, default 1, 0 up to 11
• To modify the power limit for a disk group
  alter diskgroup dgroup1 rebalance power 11
• Check on the status via VASM_OPERATION

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Basic ASM Commands Database level

• Set for default diskgroupdb_create_file_destD
  GROUP1
• Create tablespaces without names using
  OMFCREATE TABLESPACE testts DATAFILE SIZE
  5gALTER TABLESPACE testts ADD DATAFILE SIZE
  10g

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Basic ASM Commands Database level

• Set for default diskgroup for logfiles
• db_create_online_log_dest_1DGROUP1
• db_create_online_log_dest_2DGROUP1
• Create redo logs without names using OMFALTER
  SYSTEM ADD LOGFILE SIZE 200m

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Caveats

• If ASM goes down, all instance that use ASM will
  immediately crash.
• Normal or high redundancy may not show the actual
  disk use
• Databases can remain unnoticed if not dropped
• Loss of a disk (when using external redundancy)
  will result in the loss of the diskgroup

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ASM Myths and Legends

• ASM will automatically rebalance hot spots
• ASM controls file I/O
• ASM must run on RAID 10
• Disks/Luns must be added to a diskgroup in
  multiples of 4 or 8

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• Quick Guide to 11gR2
• New Features

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3rd Party FS
Application
Database RAC
Automatic Storage Management (ASM)
ACFS Snapshot
ASM Instance Managing Oracle DB Files
ASM Cluster Single Node File System (ACFS)
ASM Files
ASM Disk Group
DB Datafiles
DB Datafiles
DB Datafiles
OCR Voting files
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Oracle Database 11g Release 2Automatic Storage
Management (ASM)

• The foundation for Grid Storage

PSFT
Siebel
EBS
Web
Automatic Storage Management
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New in 11gR2

• ASM part of the clusterware
• ACFS
• ASMCA, ASMCMD
• RAC - OCR/Voting disks in ASM
• Diskgroup rename

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Recommended Reading

• www.oracle.com/technology/asm - Oracle White
  Papers
• www.oracleracsig.com Oracle RAC SIG
• www.oracle-base.com/articles/10g/ASMUsingASMLibAnd
  RawDevices.php
• www.juliandyke.com Author Julian Dyke
• www.idevelopment.info Jeff Hunter

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More information

• Contact jay.caviness_at_mckesson.com
• Corporate www.mckesson.com/clinicals
• Personal www.grumpy-dba.com