Single Client Access Name

8/21/2019 Single Client Access Name

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Single client access name (SCAN) is introduced in Oracle 11g R2 Cluster Ready

Software(CRS) to simplify the database connection strings that an Oracle Client uses to

connect to an Oracle Cluster atabase! " ha#e recei#ed a few emails about SCAN setup

issues and " ha#e promised that " would come up with an article addressing the following

$uestions%

1! What is SCAN in Oracle 11g R2 RAC?

2! How does SCAN work ?

&! How to setup DNS for Oracle 11g R2 SCAN?

'! How to setup NS for Oracle 11g R2 SCAN?

! How to install Oracle 11g R2 RAC without SCAN Setup in DNS or NS?

! How to !o"e SCAN fro! DNS to #etc#hosts?

*! How to !o"e SCAN fro! #etc#hosts to DNS?

+! How to rena!e SCAN in Cluster?

,! How to rena!e SCAN $ort in Cluster?

-hat is SCAN in Oracle 11g R2 RAC.

Single client access name (SCAN) is meant to facilitate single name for all Oracle clients to

connect to the cluster database/ irrespecti#e of number of nodes and node location! 0ntil

now/ we ha#e to eep adding multiple address records in all clients tnsnames!ora/ when a

new node gets added to or deleted from the cluster!

Client NS 3ntry in pre 11gR2 RAC en"iron!ents%

4oid15rac1 admin67cat tnsnames!ora

O"8 9

(3SCR":"ON 9 (AR3SS 9 (:ROOCO; 9 C:)(NA@3 9 oid!freeoraclehelp!com)

)

)

http://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#WHATISSCANINORAChttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#HOWDOESSCANWORKhttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#ORACLE11GR2SCANDNShttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#ORACLE11GR2SCANGNShttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#ORACLE11GR2RACINShttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#HOWTOMOVESCANTOHOSTShttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#HOWTOMOVESCANTODNShttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#HOWTORENAMESCANNAMEhttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#HOWTORENAMESCANPORThttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#HOWDOESSCANWORKhttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#ORACLE11GR2SCANDNShttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#ORACLE11GR2SCANGNShttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#ORACLE11GR2RACINShttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#HOWTOMOVESCANTOHOSTShttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#HOWTOMOVESCANTODNShttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#HOWTORENAMESCANNAMEhttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#HOWTORENAMESCANPORThttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#WHATISSCANINORAC


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4oid15rac1 admin67tnsping oiddb

NS :ing 0tility for ;inu% ?ersion 11!2!B!2!B = :roduction on 1=3C=2B11 1'%21%1+

Copyright (c) 1,,*/ 2B1B/ Oracle! All rights reser#ed!

0sed parameter les%

0sed NSNA@3S adapter to resol#e the alias

Attempting to contact (3SCR":"ON 9 (AR3SS 9 (:ROOCO; 9 C:)(NA@3 9 oid!freeoraclehelp!com)))

OD (1B msec)

4oid15rac1 admin67s$lplus system5oiddb

SE;F:lus% Release 11!2!B!2!B :roduction on hu ec 1 1'%21%&2 2B11

Copyright (c) 1,+2/ 2B1B/ Oracle! All rights reser#ed!

3nter password%

Connected to%

Oracle atabase 11g 3nterprise 3dition Release 11!2!B!2!B = :roduction

-ith the :artitioning/ Real Application Clusters/ Automatic Storage @anagement/ O;A:/

ata @ining and Real Application esting options

SE;G

As you see abo#e/ we got to list all the addresses of all 8 nodes! "f the cluster has got more

than cluster nodes/ we got to list each and e#ery node out here! his need to be updated

when a new node is added or eisting node is remo#ed!

O"8 9 (3SCR":"ON 9

(AR3SS 9 (:ROOCO; 9 C:)(


3/22

(CONN3C>AA 9 (S3R?3R 9 3"CA3) (S3R?"C3>NA@3 9 oid!freeoraclehelp!com)

)

)

his is big problem when the cluster has many nodes and end user application maes

connections to the databases! SCAN would help us easily manage the 8 Connection strings

in Client tnsnames!ora les!


4/22

-ith the :artitioning/ Real Application Clusters/ Automatic Storage @anagement/ O;A:/

ata @ining and Real Application esting options

SE;G

So/ you would see only one SCAN AR3SS in tnsnames!ora les no matter how manynodes in the cluster are!

(AR3SS 9 (:ROOCO; 9 C:)(


5/22

connect(/ Lsa>family9AM>M";3/ path9#arrunnscdsocetP/ 11B) 9 =1 3NO3N (No such le or directory)

connect(+/ Lsa>family9AM>M";3/ path9#arrunnscdsocetP/ 11B) 9 =1 3NO3N (No such le or directory)

connect(+/ Lsa>family9AM>M";3/ path9#arrunnscdsocetP/ 11B) 9 =1 3NO3N (No such le or directory)

connect(+/ Lsa>family9AM>"N3/ sin>port9htons(B)/ sin>addr9inet>addr(1,2!1+!1!1B)P/ 1) 9 B

connect(,/ Lsa>family9AM>"N3/ sin>port9htons(&)/ sin>addr9inet>addr(1,2!1+!1!2B)P/ 2+) 9 B






connect(,/ Lsa>family9AM>"N3/ sin>port9htons(121)/ sin>addr9inet>addr(1,2!1+!1!2&)P/ 1) 9 B

connect(,/ Lsa>family9AM>"N3/ sin>port9htons(121)/ sin>addr9inet>addr(1,2!1+!1!2')P/ 1) 9 B

connect(,/ Lsa>family9AM>"N3/ sin>port9htons(121)/ sin>addr9inet>addr(1,2!1+!1!2)P/ 1) 9 B







connect(,/ Lsa>family9AM>"N3/ sin>port9htons(B)/ sin>addr9inet>addr(1,2!1+!1!2')P/ 1) 9 B

connect(,/ Lsa>family9AM>"N3/ sin>port9htons(B)/ sin>addr9inet>addr(1,2!1+!1!2)P/ 1) 9 B

connect(,/ Lsa>family9AM>"N3/ sin>port9htons(B)/ sin>addr9inet>addr(1,2!1+!1!2&)P/ 1) 9 B

connect(,/ Lsa>family9AM>"N3/ sin>port9htons(121)/ sin>addr9inet>addr(1,2!1+!1!2)P/ 1) 9 =1

3"N:ROHR3SS (Operation now in progress)

connect(,/ Lsa>family9AM>"N3/ sin>port9htons(121)/ sin>addr9inet>addr(1,2!1+!1!11)P/ 1) 9 =1

3"N:ROHR3SS (Operation now in progress)

1,2!1+!1!2 is one of the SCAN ":s and 1,2!1+!1!11 is the ?": of the rst RAC node!

4oid15rac1 Q67 nslooup 1,2!1+!1!11

Ser#er% 1,2!1+!1!2B

Address% 1,2!1+!1!2B&

11!1!1+!1,2!in=addr!arpa name 9 rac1=#ip!freeoraclehelp!com!

4oid15rac1 Q67 nslooup 1,2!1+!1!2

Ser#er% 1,2!1+!1!2B

Address% 1,2!1+!1!2B&

2!1!1+!1,2!in=addr!arpa name 9 scan!freeoraclehelp!com!

4oid15rac1 Q67 nslooup scan!freeoraclehelp!com

Ser#er% 1,2!1+!1!2B

Address% 1,2!1+!1!2B&


6/22

Name% scan!freeoraclehelp!com

Address% 1,2!1+!1!2


Address% 1,2!1+!1!2&


Address% 1,2!1+!1!2'

4oid15rac1 Q67

So/ SCAN needs to resol#e to one to three ": addresses with the same name! Oracle

recommends using three ": Addresses for SCAN in NS! here would be three SCAN listeners

only/ though the cluster has got doens of nodes! SCAN listeners would be started from HR"

Oracle


7/22

2! Oracle client connects using SCAN name% myscan%121sales!eample!com

&! Client $ueries NS to resol#e scan_name!

'! SCAN listener selects least loaded node (node in this eample)

! he client connects to the local listener on node2! he local listener starts a

dedicated ser#er process for the connection to the database!

! he client connects directly to the dedicated ser#er process on node2 and accesses

the sales2 database instance!

SE;G show parameter local>listener

NA@3 K:3 ?A;03

==================== ========= =========

local>listener string (3SCR":"ON9(AR3SS>;"S9(AR3SS9(:ROOCO;9C:)

(listener

NA@3 K:3 ?A;03

==================== ========= =========

remote>listener string scan!freeoraclehelp!com%121

SE;G

After the installation/ two SCAN listeners would be started on one node and another SCANlistener on another node in a two node cluster!

4grid5rac1 Q67sr#ctl cong scan

SCAN name% scan!freeoraclehelp!com/ Networ% 11,2!1+!1!B2!2!2!BethB

SCAN ?": name% scan1/ ":% scan!freeoraclehelp!com1,2!1+!1!2

SCAN ?": name% scan2/ ":% scan!freeoraclehelp!com1,2!1+!1!2&

SCAN ?": name% scan&/ ":% scan!freeoraclehelp!com1,2!1+!1!2'

4grid5rac1 Q67sr#ctl cong scan>listener

SCAN ;istener ;"S3N3R>SCAN1 eists! :ort% C:%121


SCAN ;istener ;"S3N3R>SCAN& eists! :ort% C:%121

4grid5rac1 Q67crsctl stat res =w K:3 9 ora!scan>listener!type

NA@39ora!;"S3N3R>SCAN1!lsnr

K:39ora!scan>listener!type

ARH39ON;"N3

SA39ON;"N3 on rac1

NA@39ora!;"S3N3R>SCAN2!lsnr


8/22


ARH39ON;"N3

SA39ON;"N3 on rac2

NA@39ora!;"S3N3R>SCAN&!lsnr


ARH39ON;"N3

SA39ON;"N3 on rac2

4grid5rac1 Q67

4grid5rac1 Q67ps =efUgrep tnsl

oracle +*& 1 B 1&%11 . BB%BB%BB oracleproduct11!2!B11!2!Bgridbintnslsnr ;"S3N3R>SCAN1 =inherit

oracle +,2 1 B 1&%11 . BB%BB%BB oracleproduct11!2!B11!2!Bgridbintnslsnr ;"S3N3R =inherit

4grid5rac1 Q67

4grid5rac1 Q67lsnrctl status ;"S3N3R>SCAN1

;SNRC; for ;inu% ?ersion 11!2!B!2!B = :roduction on 1=3C=2B11 1%1&%'+

Copyright (c) 1,,1/ 2B1B/ Oracle! All rights reser#ed!

Connecting to (3SCR":"ON9(AR3SS9(:ROOCO;9":C)(D3K9;"S3N3R>SCAN1)))

SA0S of the ;"S3N3R

========================

Alias ;"S3N3R>SCAN1

?ersion NS;SNR for ;inu% ?ersion 11!2!B!2!B = :roduction

Start ate 1=3C=2B11 1&%11%1

0ptime B days 2 hr! 2 min! && sec

race ;e#el oV

Security ON% ;ocal OS Authentication

SN@: OMM

;istener :arameter Mile oracleproduct11!2!B11!2!Bgridnetworadminlistener!ora

;istener ;og Mile oracleproduct11!2!B11!2!Bgridlogdiagtnslsnrrac1listener>scan1alertlog!ml

;istening 3ndpoints Summary!!!

(3SCR":"ON9(AR3SS9(:ROOCO;9ipc)(D3K9;"S3N3R>SCAN1)))

(3SCR":"ON9(AR3SS9(:ROOCO;9tcp)(


9/22


oracle +&B 1 B 12%&+ . BB%BB%BB oracleproduct11!2!B11!2!Bgridbintnslsnr ;"S3N3R>SCAN& =inherit

oracle +&& 1 B 12%&+ . BB%BB%BB oracleproduct11!2!B11!2!Bgridbintnslsnr ;"S3N3R>SCAN2 =inherit

oracle +& 1 B 12%&+ . BB%BB%BB oracleproduct11!2!B11!2!Bgridbintnslsnr ;"S3N3R =inherit

oracle *'2& *&*2 B 1%1' pts1 BB%BB%BB grep tnsl

4grid5rac2 Q67


;SNRC; for ;inu% ?ersion 11!2!B!2!B = :roduction on 1=3C=2B11 1%1'%B'



SA0S of the ;"S3N3R

========================

Alias ;"S3N3R>SCAN2


Start ate 1=3C=2B11 12%&+%'

0ptime B days 2 hr! & min! 1, sec

race ;e#el oV


SN@: OMM







10/22

0ptime B days 2 hr! & min! 21 sec

race ;e#el oV


SN@: OMM


;istener ;og Mile oracleproduct11!2!B11!2!Bgridlogdiagtnslsnrrac2listener>scan&alertlog!ml


(3SCR":"ON9(AR3SS9(:ROOCO;9ipc)(D3K9;"S3N3R>SCAN&)))



11/22

subdomain to HNS! Mor eample/ if your company domain is freeoraclehelp!com/ youJre

going to create grid!freeoraclehelp!com in the NS Ser#ers of freeoraclehelp!com and

delegate looups for grid!freeoraclehelp!com to HNS ?":!

elegate to HNS Ser#er in NS Ser#ers

grid!freeoraclehelp!com NS gns#ip!freeoraclehelp!com

Address Record for the HNS ?":

gns#ip!freeoraclehelp!com! 1,2!1+!1!&1

Once subdomain is complete/ looups for the subdomain names from the main domain

would be forwarded to HNS Ser#ices! Kou would be entering the subdomain name and HNS

?": during the Hrid "nfrastructure installation!


12/22

Oracle 11gR2 RAC ,nstallation with NS- without SCAN eplains the Oracle 11g R2

RAC installation with HNS!


13/22

SCAN1!lsnrI/ but the force option was not specied

:RCR=1B % Mailed to stop resource ora!scan2!#ip

CRS=22,% 0nable to act on Iora!scan2!#ipI because that would re$uire stopping or relocating

Iora!;"S3N3R>SCAN2!lsnrI/ but the force option was not specied

:RCR=1B % Mailed to stop resource ora!scan&!#ip

CRS=22,% 0nable to act on Iora!scan&!#ipI because that would re$uire stopping or relocating

Iora!;"S3N3R>SCAN&!lsnrI/ but the force option was not specied

Stop the scan>listener rst and then stop scan resource

4grid5rac1 Q67sr#ctl stop scan>listener

4grid5rac1 Q67sr#ctl stop scan



oracle ,'B 1 B 1&%11 . BB%BB%BB oracleproduct1B!2!Brdbmsbintnslsnr O">RAC1 =inherit

4grid5rac1 Q67

2! Add an entry in etchosts le for SCAN name%

4root5rac2 Q6 nslooup scan!freeoraclehelp!com

Ser#er% 1,2!1+!1!2B

Address% 1,2!1+!1!2B&


Address% 1,2!1+!1!2


Address% 1,2!1+!1!2&


Address% 1,2!1+!1!2'

4root5rac2 Q6 #i etcresol#!conf

nameser#er 1,2!1+!1!2B Second RAC Node


14/22

nameser#er 1,2!1+!1!1 :rimary NS in the domain

search freeoraclehelp!com ;ocal omain





4root5rac2 Q6 cat etchosts

o not remo#e the following line/ or #arious programs

that re$uire networ functionality will fail!

12*!B!B!1 localhost!localdomain localhost

:ublic

1,2!1+!1!1B rac1!freeoraclehelp!com rac1


:ri#ate

1,2!1+!2!1B rac1=pri#!freeoraclehelp!com rac1=pri#


?irtual

1,2!1+!1!11 rac1=#ip!freeoraclehelp!com rac1=#ip


SCAN 3ntry

1,2!1+!1!2 scan!freeoraclehelp!com scan

4root5rac2 Q6





:ublic



:ri#ate


1,2!1+!2!2B rac2=pri#!freeoraclehelp!com rac2=pri#?irtual



SCAN 3ntry


4root5rac1 Q6


15/22


Ser#er% 1,2!1+!1!1

Address% 1,2!1+!1!1&

FF ser#er canIt nd scan!freeoraclehelp!com% NWO@A"N

4root5rac1 Q6 ping scan!freeoraclehelp!com

:"NH scan!freeoraclehelp!com (1,2!1+!1!2) (+') bytes of data!

Mrom rac1!freeoraclehelp!com (1,2!1+!1!1B) icmp>se$9B estination se$91 estination se$92 estination


16/22

?erify that only one SCAN ;istener is started and ": is right!


oracle *,1 1 B 1%'' . BB%BB%BB oracleproduct11!2!B11!2!Bgridbintnslsnr ;"S3N3R =inherit

oracle ,1'+ ',,' B 1%1B pts2 BB%BB%BB grep tnsl

4grid5rac1 Q67


oracle ,B1' 1 B 1%2 . BB%BB%BB oracleproduct11!2!B11!2!Bgridbintnslsnr ;"S3N3R =inherit

oracle ,'1 1 B 1%1B . BB%BB%BB oracleproduct11!2!B11!2!Bgridbintnslsnr ;"S3N3R>SCAN1 =inherit

oracle ,'& *&*2 B 1%1B pts1 BB%BB%BB grep tnsl


;SNRC; for ;inu% ?ersion 11!2!B!2!B = :roduction on 1=3C=2B11 1%1B%&,



SA0S of the ;"S3N3R

========================

Alias ;"S3N3R>SCAN1


Start ate 1=3C=2B11 1%1B%1'

0ptime B days B hr! B min! 2 sec

race ;e#el oV


SN@: OMM





(3SCR":"ON9(AR3SS9(:ROOCO;9tcp)(listener


4grid5rac1 Q67


17/22

After the installation of the cluster with SCAN with one ": address in etchosts/ "f you need to

switch to NS SCAN/ here are steps!

1! Stop the SCAN% Source Hrid home/ sr#ctl stop scan>listener/ and sr#ctl stop scan then!

4grid5rac1 Q67sr#ctl stop scan>listener

4grid5rac1 Q67sr#ctl stop scan

2! Remo#ecomment the entry in etchosts le for SCAN and setup a NS name with

multiple A (three A records)/ if it is not already setup! " ha#e the SCAN setup in a NS ser#er

that runs on the second cluster node! " Zust ha#e to use it (in resol#!conf)! Mor more

information about NS Setup/ refer to How to setup DNS for Oracle 11g R2 SCAN?





:ublic



:ri#ate



?irtual



SCAN 3ntry1,2!1+!1!2 scan!freeoraclehelp!com scan

4root5rac1 Q6





:ublic



:ri#ate



?irtual



SCAN 3ntry


http://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#ORACLE11GR2SCANDNShttp://www.freeoraclehelp.com/2011/12/scan-setup-for-oracle-11g-release211gr2.html#ORACLE11GR2SCANDNS


18/22

4root5rac2 Q6










Ser#er% 1,2!1+!1!2B

Address% 1,2!1+!1!2B&


Address% 1,2!1+!1!2


Address% 1,2!1+!1!2&


Address% 1,2!1+!1!2'

&! Congure the Cluster to tae the new ?":s

As root user on one of the cluster nodes (not needed on both the nodes)%

4root5rac1 Q6 oracleproduct11!2!B11!2!Bgridbinsr#ctl modify scan =n scan!freeoraclehelp!com

As grid user on one of the cluster nodes (not needed on both the nodes)%

4grid5rac1 Q67 sr#ctl modify scan>listener =u

4grid5rac1 Q67 sr#ctl start scan>listener

?erify that conguration is right and three SCAN listeners are started!

4grid5rac1 Q67sr#ctl cong scan

SCAN name% scan!freeoraclehelp!com/ Networ% 11,2!1+!1!B2!2!2!BethB

SCAN ?": name% scan1/ ":% scan!freeoraclehelp!com1,2!1+!1!2

SCAN ?": name% scan2/ ":% scan!freeoraclehelp!com1,2!1+!1!2&

SCAN ?": name% scan&/ ":% scan!freeoraclehelp!com1,2!1+!1!2'

4grid5rac1 Q67sr#ctl cong scan>listener



19/22




oracle +*& 1 B 1&%11 . BB%BB%BB oracleproduct11!2!B11!2!Bgridbintnslsnr ;"S3N3R>SCAN1 =inherit


4grid5rac1 Q67


;SNRC; for ;inu% ?ersion 11!2!B!2!B = :roduction on 1=3C=2B11 1%1&%'+



SA0S of the ;"S3N3R

========================

Alias ;"S3N3R>SCAN1


Start ate 1=3C=2B11 1&%11%1

0ptime B days 2 hr! 2 min! && sec

race ;e#el oV


SN@: OMM





(3SCR":"ON9(AR3SS9(:ROOCO;9tcp)(SCAN2 =inheritoracle +& 1 B 12%&+ . BB%BB%BB oracleproduct11!2!B11!2!Bgridbintnslsnr ;"S3N3R =inherit

oracle *'2& *&*2 B 1%1' pts1 BB%BB%BB grep tnsl

4grid5rac2 Q67

4grid5rac2 Q67 lsnrctl status ;"S3N3R>SCAN2

;SNRC; for ;inu% ?ersion 11!2!B!2!B = :roduction on 1=3C=2B11 1%1'%B'


20/22



SA0S of the ;"S3N3R

========================

Alias ;"S3N3R>SCAN2


Start ate 1=3C=2B11 12%&+%'

0ptime B days 2 hr! & min! 1, sec

race ;e#el oV


SN@: OMM





(3SCR":"ON9(AR3SS9(:ROOCO;9tcp)(SCAN&)))



21/22

Ser#ice oid!freeoraclehelp!com has 2 instance(s)!

"nstance oid1/ status R3AK/ has 1 handler(s) for this ser#ice!!!

"nstance oid2/ status R3AK/ has 1 handler(s) for this ser#ice!!!

he command completed successfully

4grid5rac2 Q67

listener =u

4grid5rac1 Q67 sr#ctl start scan>listener

?erify that conguration is right and three SCAN listeners are started!

4grid5rac1 Q67 sr#ctl cong scan


22/22

SCAN name% newscan!freeoraclehelp!com/ Networ% 11,2!1+!1!B2!2!2!BethB

SCAN ?": name% scan1/ ":% newscan!freeoraclehelp!com1,2!1+!1!&'

SCAN ?": name% scan2/ ":% newscan!freeoraclehelp!com1,2!1+!1!&&

SCAN ?": name% scan&/ ":% newscan!freeoraclehelp!com1,2!1+!1!&2

4grid5rac1 Q67 sr#ctl cong scan>listener




4grid5rac1 Q67

SCAN1 eists! :ort% C:%122



4oid15rac1 Q67

Related :ostsOracle 11gR2 RAC

Single Client Access Name

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