Cloning an Oracle Home

You may wish to clone an Oracle Home, for example you have all your databases on a single Oracle Home but you want to separate Development from Test.  This could be so you can soak test Patch Set Updates (PSU) on Development before applying to Test and then Production.  Or you might wish to have 2 Oracle Homes, so you can patch one and then switch all databases to the patched Oracle Home for minimal downtime.

 

Copying the Oracle Home

First you need to copy the Oracle Home at file level using cp as user root as shown below:

[root@v1ex2dbadm01 ~]# cp -Rp /u01/app/oracle/product/12.1.0.2/dbhome_1 /u01/app/oracle/product/12.1.0.2/dbhome_2

Then check the Oracle Home and the Cloned Oracle Home are the same size:

[root@v1ex2dbadm01 ~]# du -h /u01/app/oracle/product/12.1.0.2/dbhome_1 --max-depth=0
12G /u01/app/oracle/product/12.1.0.2/dbhome_1
[root@v1ex2dbadm01 ~]# du -h /u01/app/oracle/product/12.1.0.2/dbhome_2 --max-depth=0
12G /u01/app/oracle/product/12.1.0.2/dbhome_2

Then repeat on all the other nodes:

[root@v1ex2dbadm02 ~]# cp -Rp /u01/app/oracle/product/12.1.0.2/dbhome_1 /u01/app/oracle/product/12.1.0.2/dbhome_2
[root@v1ex2dbadm02 ~]# du -h /u01/app/oracle/product/12.1.0.2/dbhome_1 --max-depth=0
12G /u01/app/oracle/product/12.1.0.2/dbhome_1
[root@v1ex2dbadm02 ~]# du -h /u01/app/oracle/product/12.1.0.2/dbhome_2 --max-depth=0
12G /u01/app/oracle/product/12.1.0.2/dbhome_2

 

Cloning the Oracle Home

Now we have a copy of the Oracle Home, we next need to clone using the clone.pl perl script as shown below:

/usr/bin/perl $ORACLE_HOME/clone/bin/clone.pl \
'-O"CLUSTER_NODES={v1ex2dbadm01,v1ex2dbadm02}"' \
'-O"LOCAL_NODE=v1ex2dbadm01"' ORACLE_BASE=/u01/app/oracle \
ORACLE_HOME=$ORACLE_HOME ORACLE_HOME_NAME=OraDB12Home2 '-O-noConfig'

CLUSTER_NODES = all the nodes in the cluster
LOCAL_NODE = The node you are running the command on
ORACLE_BASE = The Oracle Base defined on the Server
ORACLE_HOME = The Cloned Oracle Home, already exported
ORACLE_HOME_NAME = The name you wish to give to the Cloned Oracle Home

[root@v1ex2dbadm01 ~]# su - oracle
[oracle@v1ex2dbadm01 ~]$ export ORACLE_HOME=/u01/app/oracle/product/12.1.0.2/dbhome_2
[oracle@v1ex2dbadm01 ~]$ /usr/bin/perl $ORACLE_HOME/clone/bin/clone.pl \
> '-O"CLUSTER_NODES={v1ex2dbadm01,v1ex2dbadm02}"' \
> '-O"LOCAL_NODE=v1ex2dbadm01"' ORACLE_BASE=/u01/app/oracle \
> ORACLE_HOME=$ORACLE_HOME ORACLE_HOME_NAME=OraDB12Home2 '-O-noConfig'
./runInstaller -clone -waitForCompletion "CLUSTER_NODES={v1ex2dbadm01,v1ex2dbadm02}" "LOCAL_NODE=v1ex2dbadm01" "ORACLE_BASE=/u01/app/oracle" "ORACLE_HOME=/u01/app/oracle/product/12.1.0.2/dbhome_2" "ORACLE_HOME_NAME=OraDB12Home2" -noConfig -silent -paramFile /u01/app/oracle/product/12.1.0.2/dbhome_2/clone/clone_oraparam.ini
Starting Oracle Universal Installer...

Checking Temp space: must be greater than 500 MB. Actual 5392 MB Passed
Checking swap space: must be greater than 500 MB. Actual 24532 MB Passed
Preparing to launch Oracle Universal Installer from /tmp/OraInstall2017-06-21_02-57-14PM. Please wait ...You can find the log of this install session at:
/u01/app/oraInventory/logs/cloneActions2017-06-21_02-57-14PM.log
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 ..........
Copy files in progress.

Copy files successful.

Link binaries in progress.

Link binaries successful.

Setup files in progress.

Setup files successful.

Setup Inventory in progress.

Setup Inventory successful.

Finish Setup successful.
The cloning of OraDB12Home2 was successful.
Please check '/u01/app/oraInventory/logs/cloneActions2017-06-21_02-57-14PM.log' for more details.

Setup Oracle Base in progress.

Setup Oracle Base successful.
 .................................................. 95% Done.

As a root user, execute the following script(s):
1. /u01/app/oracle/product/12.1.0.2/dbhome_2/root.sh

Execute /u01/app/oracle/product/12.1.0.2/dbhome_2/root.sh on the following nodes:
[v1ex2dbadm01]

.................................................. 100% Done.

[oracle@v1ex2dbadm01 ~]$

Next check the re-linking is RDS not UDP:

[oracle@v1ex2dbadm01 ~]$ /u01/app/oracle/product/12.1.0.2/dbhome_2/bin/skgxpinfo
rds
[oracle@v1ex2dbadm01 ~]$

If UDP, then relink using command below:

cd $ORACLE_HOME/rdbms/lib; ORACLE_HOME=$ORACLE_HOME make -f ins_rdbms.mk ipc_rds ioracle

Then repeat on all the other nodes, remember to change LOCAL_NODE:

[root@v1ex2dbadm02 ~]# su - oracle
[oracle@v1ex2dbadm02 ~]$ export ORACLE_HOME=/u01/app/oracle/product/12.1.0.2/dbhome_2
[oracle@v1ex2dbadm02 ~]$ /usr/bin/perl $ORACLE_HOME/clone/bin/clone.pl \
> '-O"CLUSTER_NODES={v1ex2dbadm01,v1ex2dbadm02}"' \
> '-O"LOCAL_NODE=v1ex2dbadm02"' ORACLE_BASE=/u01/app/oracle \
> ORACLE_HOME=$ORACLE_HOME ORACLE_HOME_NAME=OraDB12Home2 '-O-noConfig'
./runInstaller -clone -waitForCompletion "CLUSTER_NODES={v1ex2dbadm01,v1ex2dbadm02}" "LOCAL_NODE=v1ex2dbadm02" "ORACLE_BASE=/u01/app/oracle" "ORACLE_HOME=/u01/app/oracle/product/12.1.0.2/dbhome_2" "ORACLE_HOME_NAME=OraDB12Home2" -noConfig -silent -paramFile /u01/app/oracle/product/12.1.0.2/dbhome_2/clone/clone_oraparam.ini
Starting Oracle Universal Installer...

Checking Temp space: must be greater than 500 MB. Actual 10725 MB Passed
Checking swap space: must be greater than 500 MB. Actual 24565 MB Passed
Preparing to launch Oracle Universal Installer from /tmp/OraInstall2017-06-21_03-05-37PM. Please wait ...You can find the log of this install session at:
/u01/app/oraInventory/logs/cloneActions2017-06-21_03-05-37PM.log
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Copy files in progress.

Copy files successful.

Link binaries in progress.

Link binaries successful.

Setup files in progress.

Setup files successful.

Setup Inventory in progress.

Setup Inventory successful.

Finish Setup successful.
The cloning of OraDB12Home2 was successful.
Please check '/u01/app/oraInventory/logs/cloneActions2017-06-21_03-05-37PM.log' for more details.

Setup Oracle Base in progress.

Setup Oracle Base successful.
 .................................................. 95% Done.

As a root user, execute the following script(s):
1. /u01/app/oracle/product/12.1.0.2/dbhome_2/root.sh

Execute /u01/app/oracle/product/12.1.0.2/dbhome_2/root.sh on the following nodes:
[v1ex2dbadm02]

.................................................. 100% Done.

[oracle@v1ex2dbadm02 ~]$ /u01/app/oracle/product/12.1.0.2/dbhome_2/bin/skgxpinfo
rds
[oracle@v1ex2dbadm02 ~]$

Next need to run root.sh as shown below:

[oracle@v1ex2dbadm01 ~]$ exit
logout
[root@v1ex2dbadm01 ~]# /u01/app/oracle/product/12.1.0.2/dbhome_2/root.sh
Check /u01/app/oracle/product/12.1.0.2/dbhome_2/install/root_v1ex2dbadm01.v1.com_2017-06-21_15-04-16.log for the output of root script
[root@v1ex2dbadm01 ~]#

Then repeat on all the other nodes:

[oracle@v1ex2dbadm02 ~]$ exit
logout
[root@v1ex2dbadm02 ~]# /u01/app/oracle/product/12.1.0.2/dbhome_2/root.sh
Check /u01/app/oracle/product/12.1.0.2/dbhome_2/install/root_v1ex2dbadm02.v1.com_2017-06-21_15-06-49.log for the output of root script
[root@v1ex2dbadm02 ~]#

Verify that the Cloned Oracle Home comprises of all the nodes in the cluster:

[root@v1ex2dbadm01 ~]# su - oracle
[oracle@v1ex2dbadm01 ~]$ export ORACLE_HOME=/u01/app/oracle/product/12.1.0.2/dbhome_2
[oracle@v1ex2dbadm01 ~]$ $ORACLE_HOME/OPatch/opatch lsinventory -oh $ORACLE_HOME | grep node
Rac system comprising of multiple nodes
Local node = v1ex2dbadm01
Remote node = v1ex2dbadm02
[oracle@v1ex2dbadm01 ~]$

Then repeat on all the other nodes:

[root@v1ex2dbadm02 ~]# su - oracle
[oracle@v1ex2dbadm02 ~]$ export ORACLE_HOME=/u01/app/oracle/product/12.1.0.2/dbhome_2
[oracle@v1ex2dbadm02 ~]$ $ORACLE_HOME/OPatch/opatch lsinventory -oh $ORACLE_HOME | grep node
Rac system comprising of multiple nodes
Local node = v1ex2dbadm02
Remote node = v1ex2dbadm01
[oracle@v1ex2dbadm02 ~]$

 

Switching Databases to Cloned Oracle Home

Change the Oracle Home using server control:

[oracle@v1ex2dbadm01 ~]$ srvctl config database -d V1DEV -a
Database unique name: V1DEV
Database name:
Oracle home: /u01/app/oracle/product/12.1.0.2/dbhome_1
Oracle user: oracle
Spfile: +DATAC1/V1DEV/PARAMETERFILE/spfileV1DEV.ora
Password file:
Domain:
Start options: open
Stop options: immediate
Database role: PRIMARY
Management policy: AUTOMATIC
Server pools:
Disk Groups: DATAC1,RECOC1
Mount point paths:
Services: v1jobservice
Type: RAC
Start concurrency:
Stop concurrency:
Database is enabled
Database is individually enabled on nodes:
Database is individually disabled on nodes:
OSDBA group: dba
OSOPER group: dba
Database instances: V1DEV1,V1DEV2
Configured nodes: v1ex2dbadm01,v1ex2dbadm02
Database is administrator managed
[oracle@v1ex2dbadm01 ~]$ srvctl modify database -d V1DEV -o /u01/app/oracle/product/12.1.0.2/dbhome_2
[oracle@v1ex2dbadm01 ~]$ srvctl config database -d V1DEV -a
Database unique name: V1DEV
Database name:
Oracle home: /u01/app/oracle/product/12.1.0.2/dbhome_2
Oracle user: oracle
Spfile: +DATAC1/V1DEV/PARAMETERFILE/spfileV1DEV.ora
Password file:
Domain:
Start options: open
Stop options: immediate
Database role: PRIMARY
Management policy: AUTOMATIC
Server pools:
Disk Groups: DATAC1,RECOC1
Mount point paths:
Services: v1jobservice
Type: RAC
Start concurrency:
Stop concurrency:
Database is enabled
Database is individually enabled on nodes:
Database is individually disabled on nodes:
OSDBA group: dba
OSOPER group: dba
Database instances: V1DEV1,V1DEV2
Configured nodes: v1ex2dbadm01,v1ex2dbadm02
Database is administrator managed
[oracle@v1ex2dbadm01 ~]$

Next change /etc/oratab to reflect the new Oracle Home:

[oracle@v1ex2dbadm01 ~]$ vi /etc/oratab
[oracle@v1ex2dbadm01 ~]$ more /etc/oratab | grep dbhome_2
V1DEV1:/u01/app/oracle/product/12.1.0.2/dbhome_2:N # line added by Agent

Then repeat on all the other nodes:

[oracle@v1ex2dbadm02 ~]$ vi /etc/oratab
[oracle@v1ex2dbadm02 ~]$ more /etc/oratab | grep dbhome_2
V1DEV2:/u01/app/oracle/product/12.1.0.2/dbhome_2:N # line added by Agent

Now we rolling bounce the database:

[oracle@v1ex2dbadm01 ~]$ srvctl status database -d V1DEV -v
Instance V1DEV1 is running on node v1ex2dbadm01. Instance status: Open,Running from Old Oracle Home.
Instance V1DEV2 is running on node v1ex2dbadm02 with online services v1jobservice. Instance status: Open,Running from Old Oracle Home.
[oracle@v1ex2dbadm01 ~]$ srvctl stop instance -d V1DEV -i V1DEV1 -f
[oracle@v1ex2dbadm01 ~]$ srvctl start instance -d V1DEV -i V1DEV1
[oracle@v1ex2dbadm01 ~]$ srvctl stop instance -d V1DEV -i V1DEV2 -f
[oracle@v1ex2dbadm01 ~]$ srvctl start instance -d V1DEV -i V1DEV2
[oracle@v1ex2dbadm01 ~]$ srvctl status database -d V1DEV -v
Instance V1DEV1 is running on node v1ex2dbadm01. Instance status: Open.
Instance V1DEV2 is running on node v1ex2dbadm02 with online services v1jobservice. Instance status: Open.
[oracle@v1ex2dbadm01 ~]$

 

Related My Oracle Support (MOS) notes:

Master Note For Cloning Oracle Database Server ORACLE_HOME’s Using the Oracle Universal Installer (OUI) (Doc ID 1154613.1)

Cloning An Existing Oracle Database 12c Release 1 (12.1.0.x) RDBMS Installation Using OUI (Doc ID 1493677.1)

Minimal downtime patching via cloning 11gR2 ORACLE_HOME directories (Doc ID 1136544.1)

 

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Thanks

Zed DBA (Zahid Anwar)

Assess Performance using Calibrate on Exadata

For those who are fortunate to have an Oracle Exadata Database Machine, may wonder if their Exadata meets the IOPS/MBPS as per the technical specifications.  Well with the command CALIBRATE in CellCLI, you can run raw performance tests on the cells’ hard disks and flash drives, enabling you to verify the disk/drive performance:

[root@v1ex1celadm01 ~]# cellcli
CellCLI: Release 12.1.2.3.4 - Production on Tue Jun 13 19:02:05 IST 2017

Copyright (c) 2007, 2016, Oracle. All rights reserved.

CellCLI> calibrate force;
Calibration will take a few minutes...
Aggregate random read throughput across all hard disk LUNs: 1823 MBPS
Aggregate random read throughput across all flash disk LUNs: 9973 MBPS
Aggregate random read IOs per second (IOPS) across all hard disk LUNs: 3002
Calibrating hard disks (read only) ...
LUN 0_0 on drive [8:0 ] random read throughput: 152.00 MBPS, and 243 IOPS
LUN 0_1 on drive [8:1 ] random read throughput: 157.00 MBPS, and 246 IOPS
LUN 0_10 on drive [8:10 ] random read throughput: 161.00 MBPS, and 253 IOPS
LUN 0_11 on drive [8:11 ] random read throughput: 157.00 MBPS, and 251 IOPS
LUN 0_2 on drive [8:2 ] random read throughput: 157.00 MBPS, and 244 IOPS
LUN 0_3 on drive [8:3 ] random read throughput: 158.00 MBPS, and 245 IOPS
LUN 0_4 on drive [8:4 ] random read throughput: 156.00 MBPS, and 248 IOPS
LUN 0_5 on drive [8:5 ] random read throughput: 161.00 MBPS, and 250 IOPS
LUN 0_6 on drive [8:6 ] random read throughput: 159.00 MBPS, and 252 IOPS
LUN 0_7 on drive [8:7 ] random read throughput: 158.00 MBPS, and 251 IOPS
LUN 0_8 on drive [8:8 ] random read throughput: 157.00 MBPS, and 251 IOPS
LUN 0_9 on drive [8:9 ] random read throughput: 159.00 MBPS, and 254 IOPS
Calibrating flash disks (read only, note that writes will be significantly slower) ...
LUN 1_1 on drive [FLASH_1_1] random read throughput: 2,157.00 MBPS, and 280525 IOPS
LUN 2_1 on drive [FLASH_2_1] random read throughput: 2,156.00 MBPS, and 274304 IOPS
LUN 4_1 on drive [FLASH_4_1] random read throughput: 2,158.00 MBPS, and 282083 IOPS
LUN 5_1 on drive [FLASH_5_1] random read throughput: 2,160.00 MBPS, and 287786 IOPS
CALIBRATE results are within an acceptable range.
Calibration has finished.

CellCLI>

 

The CALIBRATE FORCE, allows the test to run when CELLSRV is still up, this is acceptable if there is no user workload.  It is therefore recommended to not run during normal operations.  Without the FORCE, the CELLSRV must be shut down.

PLEASE NOTE: This is a single run on a single storage cell, you will need to run on all storage cells in the Exadata Machine to get the total IOPS/MBPS.  You can use dcli to run this across all the cells 🙂

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Thanks

Zed DBA (Zahid Anwar)

SNMP unresponsive on Storage Cell after Exadata Patching

After a round of Exadata patching, the Storage Cells become unresponsive to SNMP for monitoring tools like OpsViews:

check_snmp_sysinfo CRITICAL - Agent not responding, tried SNMP v1 and v2c

This is because the Storage Cells get re-imaged as part of the Exadata patching, confirmed by imagehistory:

[root@v1ex1celadm01 ~]# imagehistory
Version : 12.1.2.1.1.150316.2
Image activation date : 2015-05-01 16:10:10 -0700
Imaging mode : fresh
Imaging status : success

Version : 12.1.2.1.3.151021
Image activation date : 2015-12-16 05:25:21 +0000
Imaging mode : out of partition upgrade
Imaging status : success

Version : 12.1.2.2.1.160330
Image activation date : 2016-05-12 14:02:43 +0100
Imaging mode : out of partition upgrade
Imaging status : success

Version : 12.1.2.3.2.160721
Image activation date : 2016-10-05 01:45:42 +0100
Imaging mode : out of partition upgrade
Imaging status : success

Version : 12.1.2.3.3.161208
Image activation date : 2017-01-18 02:53:10 +0000
Imaging mode : out of partition upgrade
Imaging status : success

Version : 12.1.2.3.4.170111
Image activation date : 2017-05-23 10:58:24 +0100
Imaging mode : out of partition upgrade
Imaging status : success

[root@v1oex1celadm01 ~]#

Which knocks out the configuration in iptables and snmpd.conf.

To resolve add back in the lines for your primary and secondary monitoring servers, for example:

rocommunity V12V1 192.168.0.31
rocommunity V12V1 192.168.0.32

So looks like this:

[root@v1ex1celadm01 ~]# more /etc/snmp/snmpd.conf
trapcommunity public
trapsink 127.0.0.1 public
rocommunity public 127.0.0.1
rocommunity V12V1 192.168.0.31
rocommunity V12V1 192.168.0.32
rwcommunity public 127.0.0.1

access RWGroup "" any noauth exact all all all
com2sec snmpclient 127.0.0.1 public
group RWGroup v1 snmpclient

pass .1.3.6.1.4.1.4413.4.1 /usr/bin/ucd5820stat
pass .1.3.6.1.4.1.3582 /usr/sbin/lsi_mrdsnmpmain

syscontact Root <root@localhost> (configure /etc/snmp/snmp.local.conf)
syslocation Unknown (edit /etc/snmp/snmpd.conf)

view all included .1 80

[root@v1ex1celadm01 ~]#

Then reload snmp using the user root:

[root@v1ex2celadm01 ~]# service snmpd reload
Reloading snmpd: [ OK ]
[root@v1ex2celadm01 ~]#

Next add the monitoring servers primary and secondary to iptables as follows:

[root@v1ex1celadm01 ~]# iptables -I INPUT -s 192.168.0.31 -p udp --dport 161 -j ACCEPT
[root@v1ex1celadm01 ~]# iptables -I INPUT -s 192.168.0.32 -p udp --dport 161 -j ACCEPT

And make permanent by saving to firewall rules:

[root@v1ex1dbadm01 ~]# /etc/init.d/iptables save
iptables: Saving firewall rules to /etc/sysconfig/iptables:[ OK ]
[root@v1ex1dbadm01 ~]#

Now your monitoring should return as SNMP connectivity is restored 🙂 :

SNMP OK - "Linux v1ex1celadm01.v1.com 2.6.39-400.294.1.el6uek.x86_64 #1 SMP Wed Jan 11 08:46:38 PST 2017 x86_64"

 

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Thanks

Zed DBA (Zahid Anwar)

ORA-00322: log 41 of thread 2 is not current copy

On a Data Guard Physical Standby, I noticed the following in the alert log:

Fri Jan 13 08:12:39 2017 
Errors in file /u01/app/oracle/diag/rdbms/v1s/V1S1/trace/V1S1_arc1_399861.trc: 
ORA-00322: log 41 of thread 2 is not current copy 
ORA-00312: online log 41 thread 2: '+RECOC1/V1S/ONLINELOG/group_41.3099.912775569' 
ORA-00322: log 41 of thread 2 is not current copy 
ORA-00312: online log 41 thread 2: '+DATAC1/V1S/ONLINELOG/group_41.807.912775567'

If you read metalink note:

Physical standby – alert*log shows ORA-322, ORA-312 intermittently (Doc ID 1592057.1)

SYMPTOMS

alert<SID>.log shows intermittently ORA-322 and ORA-312 for SRLs (standby redo logs).

CAUSE

These errors are written due to a very small timing window, when the SRL header
is being updated to reflect new content from the primary and in the same way
the ARCH process is doing its activity and seeing a CF flag entry that reflects an earlier
state.

SOLUTION

check the alert<SID>.log for any further issues. As long as ORA-322, ORA-312 is not combined with other issues, you can ignore this error.

Related Issue:

ORA-00314: log 42 of thread 2, expected sequence# 37363 doesn’t match 37361

If you found this blog post useful, please like as well as follow me through my various Social Media avenues available on the sidebar and/or subscribe to this oracle blog via WordPress/e-mail.

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Zed DBA (Zahid Anwar)

Using Linux Screen to protect against network breaks

When I carried out my first Exadata patching, I came across ‘Linux Screen‘ in the documentation, which Oracle recommended to use when patching:

“It’s recommended to run the dbnodeupdate.sh session using the Linux ‘screen’ or ‘vnc’ utility such that when a network problem breaks the connection to the server the patching session continues.”

Basically ‘Linux Screen‘ allows you to:

  1. Have a shell that can be reconnected to if you lose your connection due to network break, accidental close of terminal, the machine running the terminal crashes, etc. We’ve all been there, but now you can have the ability to protect yourself from these issues 🙂
  2. Disconnect from your screen session and reconnect to the same session at a later point in time, i.e. disconnect at the office, go home, reconnect when back home or kick off a long batch, disconnect, reconnect later to see if it’s completed.
  3. Open multiple windows within the one screen session.

Install Linux Screen

Linux screen is available from Oracle and can be downloaded via Oracle Public-yum:

[root@v1ex1dbadm01 ~]# yum install screen
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package screen.x86_64 0:4.0.3-19.el6 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

==============================================================================================================================================================================================================================================
 Package Arch Version Repository Size
==============================================================================================================================================================================================================================================
Installing:
 screen x86_64 4.0.3-19.el6 ol6_latest 494 k

Transaction Summary
==============================================================================================================================================================================================================================================
Install 1 Package(s)

Total download size: 494 k
Installed size: 795 k
Is this ok [y/N]: y
Downloading Packages:
screen-4.0.3-19.el6.x86_64.rpm | 494 kB 00:00
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Warning: RPMDB altered outside of yum.
 Installing : screen-4.0.3-19.el6.x86_64 1/1
 Verifying : screen-4.0.3-19.el6.x86_64 1/1

Installed:
 screen.x86_64 0:4.0.3-19.el6

Complete!
[root@v1ex1dbadm01 ~]#

To manually install:

[root@v1ex1dbadm01 patches]# rpm -i screen-4.0.3-19.el6.x86_64.rpm
[root@v1ex1dbadm01 patches]# rpm -qa | grep screen
screen-4.0.3-19.el6.x86_64
[root@v1ex1dbadm01 patches]# which screen
/usr/bin/screen
[root@v1ex1dbadm01 patches]#

RPMs are available via Oracle Public-yum:

http://public-yum.oracle.com/oracle-linux-5.html

http://public-yum.oracle.com/oracle-linux-6.html

Examples:

Oracle Linux 5, Update 11:

http://public-yum.oracle.com/repo/OracleLinux/OL5/11/base/x86_64/getPackage/screen-4.0.3-4.el5.x86_64.rpm

Oracle Linux 6, Update 8:

http://public-yum.oracle.com/repo/OracleLinux/OL6/8/base/x86_64/getPackage/screen-4.0.3-19.el6.x86_64.rpm

Starting Linux Screen

To start Linux Screen:

[root@v1ex1dbadm01 ~]# screen

Linux Screen Commands

Linux Screen commands are used by first pressing “CTRL” then “a“, followed by command key:

Example: “CTRL” then “a” then “?” get you the following help screen:

Screen key bindings, page 1 of 1.

Command key: ^A Literal ^A: a

break ^B b displays * help ? lockscreen ^X x number N quit \ screen ^C c title A writebuf >
clear C dumptermcap . history { } log H only Q readbuf < select ' vbell ^G xoff ^S s
colon : fit F info i login L other ^A redisplay ^L l silence _ version v xon ^Q q
copy ^[ [ flow ^F f kill K k meta a pow_break B remove X split S width W
detach ^D d focus ^I lastmsg ^M m monitor M pow_detach D removebuf = suspend ^Z z windows ^W w
digraph ^V hardcopy h license , next ^@ ^N sp n prev ^H ^P p ^? reset Z time ^T t wrap ^R r

^] paste .
" windowlist -b
- select -
0 select 0
1 select 1
2 select 2
3 select 3
4 select 4
5 select 5
6 select 6
7 select 7
8 select 8
9 select 9
I login on
O login off
] paste .


 [Press Space or Return to end.]

Detaching from Linux Screen

To detach from Linux Screen:

CTRL” then “a” then “d

[root@v1ex1dbadm01 ~]# echo "Detaching from Linux Screen, leaving my mark :)"
Detaching from Linux Screen, leaving my mark :)
[detached]

You are at this point returned to your normal shell.

Please Note: network break, accidental close of terminal, the machine running the terminal crashes, etc, automatically detach 🙂

Reattaching to Linux Screen

To reattach to Linux Screen:

[root@v1ex1dbadm01 ~]# screen -r

You’ll now be reattached to you last session:

[root@v1ex1dbadm01 ~]# echo "Detaching from Linux Screen, leaving my mark :)"
Detaching from Linux Screen, leaving my mark :)
[root@v1ex1dbadm01 ~]#

To reattach to Linux Screen, when multiple sessions are detached, use screen -r :

[root@v1ex1dbadm01 ~]# screen -r
There are several suitable screens on:
 15090.pts-0.v1ex1dbadm01 (Detached)
 346219.pts-0.v1ex1dbadm01 (Detached)
Type "screen [-d] -r [pid.]tty.host" to resume one of them.
[root@v1ex1dbadm01 ~]# screen -r 346219.pts-0.v1ex1dbadm01

Terminating Linux Screen

Once you’re finished, just type ‘exit‘ and you’ll exit back to your normal shell:

[screen is terminating]
[root@v1ex1dbadm01 ~]# screen -r
There is no screen to be resumed.
[root@v1ex1dbadm01 ~]#

You can also use:

CTRL” then “a” then “k“:

Really kill this window [y/n]y
[screen is terminating]

Advance Uses

Creating multiple screen in one session

You can add screen to your current session by:

CTRL” then “a” then “c

You’ll notice your putty session will say something like:

[screen 1:bash]root@v1ex1dbadm01:~

Screen ID starts with 0 and increases by 1 for every new screen created.

Switching between multiple screens in one session

You can switch between multiple screens, by going next and previous:

Next: “CTRL” then “a” then “n

Previous: “CTRL” then “a” then “p

You’ll notice the screen ID change as well as the screen.

Closing is the same as terminating Linux Screen, either type ‘exit‘ or “CTRL” then “a” then “k“.  You’ll need to do this for every screen until all are closed and then you will get:

[screen is terminating]

Known Issues

Cannot open your terminal

If you get the following error message:

[oracle@v1ex1dbadm01 ~]$ screen
Cannot open your terminal '/dev/pts/0' - please check.

Simple run Linux Screen as the user ‘root’ and then su to the desired user:

[root@v1ex1dbadm01 ~]# screen
[root@v1ex1dbadm01 ~]# su - oracle
[oracle@v1ex1dbadm01 ~]$

Scrollbar doesn’t work

You can enter copy mode (not sure why it’s call that, but it lets you navigate):

CTRL” then “a” then “esc” then “up“/”down

Or even better add the follow line to the root ~/.screenrc file:

termcapinfo xterm ti@:te@

If the file doesn’t exist, create it and add the line.

Now you can use scrollbar as normal 🙂

 

There are many more features, which I haven’t yet explored, but now you’ve got the idea, you’ll be able to use ‘Linux Screen’ to your benefit 🙂

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Thanks

Zed DBA (Zahid Anwar)