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

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Presentation on theme: "Bare Bones ASM What Every DBA Needs to Know Jay Caviness Sr. Systems Engineer McKesson Provider Technologies."— Presentation transcript:

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

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

3 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

4 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

5 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

6 McKesson Horizon Clinicals Client Starting disk space per installation: 400GB+ Growth 20%–30% year over year Retention requirements vary by HIPAA rules, typically 7-10 years

7 Automated Storage Management

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

9 What is ASM? Automatic Storage Management 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

10 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*

11 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_TYPE=asm Acts as the mediator and definer Not foolproof, luns can be removed out from under ASM!

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

13 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 will create an entry in /etc/inittab to respawn cssd

14 ASMlib Defines disk/luns for use with ASM Only available on Linux service oracleasm /dev/oracleasm -------------------------------- ---- ----------- --------------- --------------- asm_diskgroups string DGROUP1 asm_diskstring string ORCL:VOL*

15 init+ASM.ora Only one ASM instance per node *.asm_diskgroups=DATA' *.asm_diskstring='ORCL:* -- linux *.asm_diskstring=/dev/asm_disk* -- unix *.asm_diskstring=/dev/c0t1d1* – unix *.asm_diskstring=/dev/sda1 *.instance_type='asm' *.processes=500 - Set to minimum of 25 + 15 * number of databases uses ASM for storage -------------------------------- ---- ----------- --------------- --------------- asm_diskgroups string DGROUP1 asm_diskstring string ORCL:VOL*

16 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)

17 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

18 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

19 Tools to Manage ASM SQL*Plus ASMCMD Grid Control / Database Control SRVCTL – RAC only

20 Basic ASM Commands Create a diskgroup: CREATE DISKGROUP dgroup1 DISK orcl:vol001,orcl:vol002; Drop a diskgroup DROP DISKGROUP dgroup1; To drop a diskgroup which still contains data: DROP DISKGROUP dgroup1 INCLUDING CONTENTS;

21 Basic ASM Commands Add luns to a diskgroup: ALTER DISKGROUP dgroup1 ADD DISK orcl:vol006; Remove luns from a diskgroup: ALTER DISKGROUP dgroup1 REMOVE DISK vol006; Do both at the same time: ALTER DISKGROUP dgroup1 ADD DISK 'ORCL:VOL003','ORCL:VOL004' DROP DISK 'VOL005' REBALANCE POWER 6;

22 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 V$ASM_OPERATION

23 Basic ASM Commands – Database level Set for default diskgroup db_create_file_dest=+DGROUP1 Create tablespaces without names using OMF CREATE TABLESPACE testts DATAFILE SIZE 5g; ALTER TABLESPACE testts ADD DATAFILE SIZE 10g;

24 Basic ASM Commands – Database level Set for default diskgroup for logfiles: db_create_online_log_dest_1=+DGROUP1 db_create_online_log_dest_2=+DGROUP1 Create redo logs without names using OMF ALTER SYSTEM ADD LOGFILE SIZE 200m;

25 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

26 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

27 Quick Guide to 11gR2 New Features

28 3 rd Party FS Application Automatic Storage Management (ASM) ASM Instance Managing Oracle DB Files ASM Cluster & Single Node File System (ACFS) Database RAC ACFS Snapshot ASM Files Dynamic Volume Manager Dynamic Volumes ACFS FS Oracle Bin 3 rd Party FS DB Datafiles OCR & Voting files ASM Disk Group

29 Oracle Database 11g Release 2 Automatic Storage Management (ASM) ` The foundation for Grid Storage Siebel Web PSFT DW ODS SOA IMDB OC4J APACHE EBS DB Datafiles OCR & Voting Files Binaries File System Automatic Storage Management

30 New in 11gR2 ASM part of the clusterware ACFS ASMCA, ASMCMD RAC - OCR/Voting disks in ASM Diskgroup rename

31 Recommended Reading - Oracle White Papers – Oracle RAC SIG – Author Julian Dyke – Jeff Hunter

32 More information Contact: Corporate: Personal:

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