Getting More Knowledge (theory) With Oracle RAC.pdf

8/9/2019 Getting More Knowledge (theory) With Oracle RAC.pdf

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A Short And Getting More Knowledge with Oracle RAC

Oracle 10g and 11g R1 RAC Architecture ...................................................................... 2 Oracle 11g R2 RAC Architecture .................................................................................... 3 IP Addresses in Oracle RAC ............................................................................................ 4

RAC Using NFS ................................................................................................................ 4 RAC Using SAN And ASM 11gR2 .................................................................................... 5 Storage ........................................................................................................................... 5 SAN (Storage Area Network).......................................................................................... 5 What is SAN ? ................................................................................................................. 5 To Check The LUN On The Unix/Linux Server Hosts: ..................................................... 5 LUN and RAID implementation (General Recommendations) ...................................... 6 Oracle RAC ..................................................................................................................... 6 The main differences between 11g R1 and 11g R2 RAC are ......................................... 6 IPMI ................................................................................................................................ 6

BMC ................................................................................................................................ 6 RACCheck ....................................................................................................................... 7 ASMCA from 11gR2 ........................................................................................................ 7 ASMCMD ........................................................................................................................ 7 What are the new features with 11g ASM? .................................................................. 7 ACFS ............................................................................................................................... 7 SRVCTL & CRSCTL Commands ........................................................................................ 8 Conclusion ...................................................................................................................... 8 Links ............................................................................................................................... 8

This article is about getting more (theoretical) knowledge with Oracle RAC I wrote the first part of this article i.e. about Oracle 10g RAC in the year 2010

to do the knowledge transfer for my two good friends who did not do trainingwith Oracle RAC

In the last year it ended up with some more input from the dear Tim Hall(oracle-base.com)

I'm indeed very much thankful to him in taking time to correct and add hissome more valuable information in this article !!! His comments are as it ismarked in red color


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Oracle 10g and 11g R1 RAC Architecture

Disk Array controllerDisk arrays located here

SAN

Fabric channel switch

Public

Network

RAC 1

RDBMS_InstanceRDBMS_HomeASM_InstanceASM_HomeCRS_Home

CRS s/w loadedo/s

EthernetGigabyte

RAC 2

RDBMS_InstanceRDBMS_Home

ASM_InstanceASM_HomeCRS_Home

CRS s/w loadedo/s


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Oracle 11g R2 RAC Architecture

Disk Array controllerDisk arrays located here

SAN

Fabric channel switch

Public

Network

RAC 1

rdbms_instancerdbms_homeasm_instancegrid_Home

CRS s/w loadedO/S

EthernetGigabyte

RAC 2

rdbms_instancerdbms_home

asm_instancegrid_home

CRS s/w loadedO/S


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By what technology Oracle RAC works with?Oracle RAC is about Cache Fusion TechnologyGood Linkhttp://www.dba-oracle.com/t_gupta_oracle_rac_cache_fusion.htm

IP Addresses in Oracle RAC

The three types of IP Addresses used in Oracle RAC are:Public IP, Private IP and Virtual IP

If these three IP addresses confuses you again and again here is my explanation that shouldmake you comfortable. So, let's begin with Virtual IP

Virtual IP : In short call it VIP IP. Used for RAC Failover. Failover here is if RACInstance XX is failed then RAC Instance YY should be available. Who is connectingthese IPs frequently? RAC Instances are connecting. Will you allow Applications orUsers to connect these IP ? Absolutely NO

Private IP : In short call it Priv IP. This takes us to the next thing that is Private IP. Forexample, If Oracle RAC is setup in a Production Environment then it is mostly on SANfor Storage or any other Storage using RAID or so.How should the Storage System and RAC communicate? Will you allow thiscommunication/data transfer on a busy network? Absolutely NO. I hope you got theanswer :)

Public IP : As it is called! The public IP address is of the Server on which the OracleRAC is created / installed

What are the benefits of implementation of RAC using NFS and RAC using SAN and ASM11gR2?

RAC Using NFS

* It is low-cost RAC Implementation but not fully HA solution . (Tim: If your NFSstorage is resilient and your storage network is resilient, this has exactly the sameresilient as any ASM solution!)

* During ASM installation, it asks how the ASM disks Redundancy should beconfigured : High or Normal or External. (Tim: All three modes are available in ASM,regardless of storage layer. You should almost always pick externally redundant anduse hardware redundancy (RAID))

* ASM disks comes from NFS. (Tim: Only if you choose to use ASM and NFS together.You dont need to use ASM if you are using NFS.)

* So, if NFS has problem then complete RAC and ASM Disks have got PROBLEM. (Tim:

If your storage network has a problem, RAC on a SAN has a problem. No different.Not a reason to choose between them.)
http://www.dba-oracle.com/t_gupta_oracle_rac_cache_fusion.htmhttp://www.dba-oracle.com/t_gupta_oracle_rac_cache_fusion.htmhttp://www.dba-oracle.com/t_gupta_oracle_rac_cache_fusion.htm


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RAC Using SAN And ASM 11gR2

* 10g ASM was not so good. (Tim: Was fine after the initial bugs were fixed) * 11g R1 ASM was good* 11g R2 ASM is powerful

* Maintaining Files are of less headache. But, ASMCMD has to be understood andlittle bit practiced. ASMCMD is very easy. (Tim: Possibly not as easy as using NFS,which just feels like using a file system. Very easy.)

Storage

SAN (Storage Area Network)

What is the difference between NAS & SAN ?

* NAS provides shared storage capacity at file level* SAN provides shared storage raw capacity/raw disk capacity at block level

(Tim: So? What does this mean for Oracle? Pretty much nothing! Oracle plays wellwith both)

What is SAN ?

* SAN is platform independent and SAN has no IP address assigned for connectivity

* SAN has wwn (World Wide Number) for connectivity

* SAN is usually with FC & Fiber Optic. Fabric Channel (FC) uses Switch basedTopology

* In SAN we have Disk Array Controller, which is very intelligent and has built inFirmware

* With the SAN Management Software, we create disk arrays and assign RAID levelto it. It is important to understand which RAID level is implemented and best suitedfor the requirement. Then a LUN Number (Logical Unit Number) is generated andattached to RAC Nodes

To Check The LUN On The Unix/Linux Server Hosts:

#] cat /proc/scsi/scsiThe same LUN can be assigned to the other Nodes


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LUN and RAID implementation (General Recommendations)

* To get good performance, it is best not to do more partitions on the LUN. Forexample, 2 LUN's are provided by SAN Admin

* 1st

LUN with RAID 1+0 for Database Files that is for ASM (Tim: Equal size andperformance of all LUNs within a disk group. Minimum of 4 LUNs per disk group.)

* 2 nd LUN with RAID 0 for Control files, Online Redolog Files and Archived Logs. (Tim:Depends. If you are multiplexing all those file types, then that is fine, but mostpeople RAID 10 everything)

* FRA (Flash Recovery Area) can be stored on Local File System or on 2 nd LUN(Tim:Ouch! All storage for RAC needs to be shared, otherwise other nodes cant performinstance recovery for a failed node.)

Oracle RAC

* RAC uses Cache Fusion Technology

* File System types :1. Local File System (ext2, ext3, ext4 and NTFS etc.)2. Shared / Global File System

* Shared / Global File System is CFS (Cluster File System)* Examples of CFS are Veritas, ASM and Oracle OCFS2 (Tim: NFS)

The main differences between 11g R1 and 11g R2 RAC are

* In 11g R1 RAC, we needed to create 3 homes, that were :1. ASM home, 2. CRS home and 3. RDBMS home

* In 11g R2 RAC, only 2 homes exists that is Grid home (asm_home + crs_home) andRDBMS home

IPMI* This is a software part of 11gR2 RAC* With IPMI Commands we can communicate with Nodes directly

BMC* Baseboard Management Card helps us from Node-Fencing problems* Node-Fencing means RAC Node coming out from Cluster* Node-Fencing is also called as Node-Affinity


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RACCheck* Oracle provide the RACcheck tool (MOS [ID 1268927.1] ) to audit the configurationof RAC, CRS, ASM, GI etc.* It supports database versions from 10.2-11.2, making it a useful starting point formost analysis

* The MOS note includes the download and setup details. If you are using 11.2.0.4 orlater you will have RACcheck by default

ASMCA from 11gR2* This is a new utility called ASM Configuration Assistant

ASMCMD* SYSASM is the new Privilege from 11g R1ASM version

* SYSASM is activated when ASM is installed and the Disks and Disk Groups can bemanaged from operating system using " asmcmd "

What are the new features with 11g ASM?

* In 10g ASM the backup of ASM Metadata was not possible* From 11g ASM, the backup of ASM Metadata is possible* If any ASM Disks or Disk Groups are corrupted then Backup of Metadata helps toget the data back

ACFS

* ASM Cluster File Systemshttp://docs.oracle.com/cd/E11882_01/server.112/e16102/asmfilesystem.htm

* Oracle ASM Cluster File System (ACFS) is a general purpose cluster file systemimplemented as part of ASM

* The only things that should not be stored in ACFS are the Grid Infrastructure homeand any Oracle f iles that can be directly stored in Oracle ASM Disks. (Tim: Recentversions allow Oracle datafiles to be stored in ACFS, but you probably shouldnt.)

* Oracle ACFS is the preferred file manager for non-database files

* Other supported files are video, audio, text, images, engineering drawings, andother general-purpose application file data.

* Starting with Oracle ASM 11 g R 2, Oracle ACFS supports RMAN backups

(BACKUPSET file type), archive logs (ARCHIVELOG file type), and Data Pumpdumpsets (DUMPSET file type)
https://support.oracle.com/CSP/main/article?cmd=show&type=NOT&doctype=SCRIPT&id=1268927.1https://support.oracle.com/CSP/main/article?cmd=show&type=NOT&doctype=SCRIPT&id=1268927.1https://support.oracle.com/CSP/main/article?cmd=show&type=NOT&doctype=SCRIPT&id=1268927.1https://support.oracle.com/CSP/main/article?cmd=show&type=NOT&doctype=SCRIPT&id=1268927.1


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SRVCTL & CRSCTL Commands* This is the way to manage Oracle RAC. The "CRS_STAT" kind of Commands are used with10g Oracle RAC and deprecated

* So, SRVCTL and CRSCTL Commands to be learned and pretty cool !

Conclusion

* To think RAC is one of the Oracle High Availability Solution is a good think. But, tothink it is the only solution is not a good thinking* Oracle provides many other HA solutions so exploring all of them is also a primarything for us to do

Links

RAC Installations

http://oracle-base.com/articles/rac/articles-rac.php

Real Application Clusters Administration and Deployment Guide (SRVCTLUsage)

http://docs.oracle.com/database/121/RACAD/srvctladmin.htm

Troubleshooting Grid Infrastructure startup (Very interesting one)

https://martincarstenbach.wordpress.com/2011/03/17/troubleshooting-grid-infrastructure-startup/
http://oracle-base.com/articles/rac/articles-rac.phphttp://oracle-base.com/articles/rac/articles-rac.phphttp://docs.oracle.com/database/121/RACAD/srvctladmin.htmhttp://docs.oracle.com/database/121/RACAD/srvctladmin.htmhttps://martincarstenbach.wordpress.com/2011/03/17/troubleshooting-grid-infrastructure-startup/https://martincarstenbach.wordpress.com/2011/03/17/troubleshooting-grid-infrastructure-startup/https://martincarstenbach.wordpress.com/2011/03/17/troubleshooting-grid-infrastructure-startup/https://martincarstenbach.wordpress.com/2011/03/17/troubleshooting-grid-infrastructure-startup/https://martincarstenbach.wordpress.com/2011/03/17/troubleshooting-grid-infrastructure-startup/http://docs.oracle.com/database/121/RACAD/srvctladmin.htmhttp://oracle-base.com/articles/rac/articles-rac.php

Getting More Knowledge (theory) With Oracle RAC.pdf

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