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SCAN

RAC 12c enhancements: adding an additional SCAN-part 1

Based on customer request Oracle has added the functionality to add a second SCAN, completely independent of the SCAN defined/created during the cluster creation. Why would you want to use this feature? A few reasons that spring to mind are:

  • Consolidation: customers insist on using a different network
  • Separate network for Data Guard traffic

To demonstrate the concept I am going to show you in this blog post how I

  1. Add a new network resource
  2. Create new VIPs
  3. Add a new SCAN
  4. Add a new SCAN listener

It actually sounds more complex than it is, but I have a feeling I need to split this article in multiple parts as it’s far too long.

The lab setup

RAC 12c enhancements: adding an additional SCAN-part 1

Based on customer request Oracle has added the functionality to add a second SCAN, completely independent of the SCAN defined/created during the cluster creation. Why would you want to use this feature? A few reasons that spring to mind are:

  • Consolidation: customers insist on using a different network
  • Separate network for Data Guard traffic

To demonstrate the concept I am going to show you in this blog post how I

  1. Add a new network resource
  2. Create new VIPs
  3. Add a new SCAN
  4. Add a new SCAN listener

It actually sounds more complex than it is, but I have a feeling I need to split this article in multiple parts as it’s far too long.

The lab setup

My COLLABORATE 12-IOUG sessions

If you are attending Collaborate 2012, you might be interested in my content-rich sessions below :

Session Number: 326
Session Title: SCAN, VIP, HAIP, and other RAC acronyms
Session Date/Time/Room: Tue, Apr 24, 2012 (10:45 AM – 11:45 AM) : Surf C

Session Number: 327
Session Title: Internals and Performance Boot Camp: Truss, pstack, pmap, and more
Session Date/Time/Room: Wed, Apr 25, 2012 (03:00 PM – 04:00 PM) : Palm A

Hope to see you there!

Update: I am uploading presentation files. Presentations are much more recent than the document :-)

DNS Config for RAC SCAN… Again…

Some time ago I wrote an article about configuring DNS for the SCAN address in Oracle 11gR2 RAC.

Over the last couple of days one of the Oakies has given me some feedback on the article based on his experiences with Oracle Linux 5.

For my virtual RAC installations I typically do the DNS configuration on the host machine, which is running Fedora. It seems Oracle Linux 5 is a little different. Just to make sure I ran through the setup on Oracle Linux 5 and 6 to see what the score was.

Where are the logs for the SCAN listeners?

Quick post and note to self. Where are the SCAN listener log files? A little bit of troubleshooting was required, but I guess I could have read the manuals too. In the end it turned out to be quite simple!

First of all, I needed to find out where on my four node cluster I had a SCAN listener. This is done quite easily by asking Clusterware:

[grid@rac11gr2node2 ~]$ srvctl status scan_listener
SCAN Listener LISTENER_SCAN1 is enabled
SCAN listener LISTENER_SCAN1 is running on node rac11gr2node2
SCAN Listener LISTENER_SCAN2 is enabled
SCAN listener LISTENER_SCAN2 is running on node rac11gr2node4
SCAN Listener LISTENER_SCAN3 is enabled
SCAN listener LISTENER_SCAN3 is running on node rac11gr2node3

I was initially on the first node, so had to ssh to the second. From there on I thought that the proc file system might have the answer. I needed to get the PID of the SCAN listener first:

[grid@rac11gr2node2 ~]$ ps -ef | grep -i scan
grid      4738     1  0 Jun03 ?        00:00:13 /u01/app/grid/product/11.2.0/crs/bin/tnslsnr LISTENER_SCAN1 -inherit
grid     24694 24147  0 20:55 pts/0    00:00:00 grep -i scan

Now /proc/4738/fd lists all the open file descriptors used by the SCAN listener. Surely the log.xml file would be there somewhere:

[grid@rac11gr2node2 ~]$ ll /proc/4738/fd
total 0
lrwx------ 1 grid oinstall 64 Jun 16 20:46 0 -> /dev/null
lrwx------ 1 grid oinstall 64 Jun 16 20:46 1 -> /dev/null
lrwx------ 1 grid oinstall 64 Jun 16 20:46 10 -> socket:[20906]
lrwx------ 1 grid oinstall 64 Jun 16 20:46 11 -> socket:[20908]
lrwx------ 1 grid oinstall 64 Jun 16 20:46 12 -> socket:[20927]
lrwx------ 1 grid oinstall 64 Jun 16 20:46 13 -> socket:[20957]
lrwx------ 1 grid oinstall 64 Jun 16 20:46 14 -> socket:[20958]
lrwx------ 1 grid oinstall 64 Jun 16 20:46 15 -> socket:[22991]
lrwx------ 1 grid oinstall 64 Jun 16 20:46 16 -> socket:[10712179]
lrwx------ 1 grid oinstall 64 Jun 16 20:46 17 -> socket:[10173760]
lrwx------ 1 grid oinstall 64 Jun 16 20:46 18 -> socket:[10176036]
lrwx------ 1 grid oinstall 64 Jun 16 20:46 19 -> socket:[9106216]
lrwx------ 1 grid oinstall 64 Jun 16 20:46 2 -> /dev/null
lr-x------ 1 grid oinstall 64 Jun 16 20:46 3 -> /u01/app/grid/product/11.2.0/crs/rdbms/mesg/diaus.msb
lr-x------ 1 grid oinstall 64 Jun 16 20:46 4 -> /proc/4738/fd
lr-x------ 1 grid oinstall 64 Jun 16 20:46 5 -> /u01/app/grid/product/11.2.0/crs/network/mesg/nlus.msb
lr-x------ 1 grid oinstall 64 Jun 16 20:46 6 -> pipe:[20893]
lr-x------ 1 grid oinstall 64 Jun 16 20:46 7 -> /u01/app/grid/product/11.2.0/crs/network/mesg/tnsus.msb
lrwx------ 1 grid oinstall 64 Jun 16 20:46 8 -> socket:[20904]
l-wx------ 1 grid oinstall 64 Jun 16 20:46 9 -> pipe:[20894]

Well maybe not. Next option is to query the listener itself via lsnrctl. Nothing easier that that:

LSNRCTL> set current_listener LISTENER_SCAN1
Current Listener is LISTENER_SCAN1
LSNRCTL> show log_file
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER_SCAN1)))
LISTENER_SCAN1 parameter "log_file" set to /u01/app/grid/product/11.2.0/crs/log/diag/tnslsnr/rac11gr2node2/listener_scan1/alert/log.xml
The command completed successfully
LSNRCTL>

Aha, it uses the ADR as well. So back there, change the base and query the file:

[grid@rac11gr2node2 ~]$ adrci

ADRCI: Release 11.2.0.1.0 - Production on Wed Jun 16 20:58:17 2010

Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

ADR base = "/u01/app/oracle"
adrci> set base /u01/app/grid/product/11.2.0/crs/log
adrci> show home
ADR Homes:
diag/tnslsnr/rac11gr2node2/listener_scan1
diag/tnslsnr/rac11gr2node2/listener_scan3
diag/tnslsnr/rac11gr2node2/listener_scan2
adrci> set home diag/tnslsnr/rac11gr2node2/listener_scan1
adrci> show alert -tail
2010-06-16 20:58:25.021000 +01:00
16-JUN-2010 20:58:25 * service_update * polstdby_1 * 0
2010-06-16 20:58:27.441000 +01:00
16-JUN-2010 20:58:27 * service_update * poldb_2 * 0
2010-06-16 20:58:30.444000 +01:00
16-JUN-2010 20:58:30 * service_update * poldb_2 * 0
16-JUN-2010 20:58:30 * service_update * poldb_1 * 0
2010-06-16 20:58:33.442000 +01:00
16-JUN-2010 20:58:33 * service_update * poldb_2 * 0
2010-06-16 20:58:35.784000 +01:00
16-JUN-2010 20:58:35 * service_update * prod1 * 0
16-JUN-2010 20:58:36 * service_update * poldb_2 * 0
16-JUN-2010 20:58:36 * service_update * poldb_1 * 0
2010-06-16 20:58:39.546000 +01:00
16-JUN-2010 20:58:39 * service_update * poldb_2 * 0
16-JUN-2010 20:58:39 * service_update * poldb_1 * 0
2010-06-16 20:58:42.574000 +01:00
16-JUN-2010 20:58:42 * service_update * poldb_2 * 0
2010-06-16 20:58:45.574000 +01:00
16-JUN-2010 20:58:45 * service_update * poldb_2 * 0
2010-06-16 20:58:48.576000 +01:00
16-JUN-2010 20:58:48 * service_update * poldb_2 * 0
16-JUN-2010 20:58:48 * service_update * poldb_1 * 0
2010-06-16 20:58:51.575000 +01:00
16-JUN-2010 20:58:51 * service_update * poldb_2 * 0
16-JUN-2010 20:58:51 * service_update * poldb_1 * 0
2010-06-16 20:58:54.578000 +01:00
16-JUN-2010 20:58:54 * service_update * poldb_2 * 0

Job done.