Setting up slewing NTP option in Linux for Oracle Database

Many times while installing/configuring Oracle Cluster, DBA’s  receive the following error message.

Checking NTP daemon command line for slewing option “-x”Check: NTP daemon command line

Node Name                     Slewing Option Set?  ————————————  ————————

vcsnode1                         no

vcsnode2                         no

Result:NTP daemon slewing option check failed on some nodes PRVF-5436 : The NTP daemon running on one or more nodes lacks the slewing option “-x”Result: Clock synchronization check using Network Time Protocol(NTP) failed

To fix this error, slewing needs to be configured.

Follow the below steps to configure slewing in Linux.

• Stop ntpd daemon using the following command.

[root@vcsnode1 ~]# service ntpd stop

Shutting down ntpd:                                        [  OK  ]

[root@vcsnode1 ~]#

• Edit /etc/sysconfig/ntpd file.  Usually the file looks as given below.

[root@vcsnode1 sysconfig]# cat ntpd
# Drop root to id ‘ntp:ntp’ by default.
OPTIONS=”-u ntp:ntp -p /var/run/ntpd.pid”

# Set to ‘yes’ to sync hw clock after successful ntpdate
SYNC_HWCLOCK=no
[root@vcsnode1 sysconfig]#

• Edit the file and add “-x” to  ”OPTIONS=”-u ntp:ntp -p /var/run/ntpd.pid”" line befor e”-u”
• After editing the file, the contents should look like given below

[root@vcsnode1 sysconfig]# cat ntpd
# Drop root to id ‘ntp:ntp’ by default.
OPTIONS=”-x -u ntp:ntp -p /var/run/ntpd.pid”

# Set to ‘yes’ to sync hw clock after successful ntpdate
SYNC_HWCLOCK=no
[root@vcsnode1 sysconfig]#

• Start ntpd daemon using the following command

[root@VCSNode2 ~]# service ntpd start

Starting ntpd:                                             [  OK  ]

[root@VCSNode2 ~]#

• Ask the DBA to install/proceed to configure Oracle Cluster

How to configure Raw Disks in RHEL 5 for Oracle11g udev

The following is to change the owner, group and permissions for raw devices used for Oracle RAC.

Create a file called /etc/udev/rules.d/65-raw-permissions.rules with these contents:

#Set permissions of raw bindings to Oracle Clusterware devices

KERNEL=="raw1", OWNER="root", GROUP="oinstall", MODE="640"

KERNEL=="raw2", OWNER="root", GROUP="oinstall", MODE="640"

KERNEL=="raw3", OWNER="oracle", GROUP="oinstall", MODE="640"

KERNEL=="raw4", OWNER="oracle", GROUP="oinstall", MODE="640"

KERNEL=="raw5", OWNER="oracle", GROUP="oinstall", MODE="640"

Test executing:

udevtest /class/raw/raw1

It should show something like:

udevtest /class/raw/raw1

main: looking at device '/class/raw/raw1' from subsystem 'raw'

udev_rules_get_name: rule applied, 'raw1' becomes 'raw/raw1'

udev_device_event: device '/class/raw/raw1' already in database, validate currently present symlinks

udev_node_add: creating device node '/dev/raw/raw1', major = '162', minor = '1', mode = '0640', uid = '0', gid = '600'

main: run: 'socket:/org/kernel/udev/monitor'

main: run: '/lib/udev/udev_run_devd'

main: run: 'socket:/org/freedesktop/hal/udev_event'

main: run: '/sbin/pam_console_apply /dev/raw/raw1 '

To apply the rules run:

# start_udev

Starting udev:                           [  OK  ]

References:

http://www.oracleflash.com/7/How-to-configure-Raw-Disks-in-RHEL-5.html

http://www.ardentperf.com/2008/02/13/oracle-clusterware-on-rhel5oel5-with-udev-and-multipath/

Procedure to upgrade Linux 6.1 to 6.4 without CD from a local repository

We are doing an upgrade of RHEL 6.1 to 6.4. It is applicable to other versions and distributions like CentOS.

1) Create a local repository to have all the packages of the new version available.

Create a file called /etc/yum.repos.d/server64.repo with the following contents:

[server64x64]

name=Red Hat Enterprise Linux 6.4 x64

baseurl=ftp://ftprepo.domain.local/RHEL/rhel64x64/Server

enabled=1

gpgcheck=1

gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release

2) Verify what is the current running version and kernel.

# uname -a

Linux SERVER1.domain.local 2.6.32-131.0.15.el6.x86_64 #1 SMP Tue May 10 15:42:40 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux

# cat /etc/redhat-release

Red Hat Enterprise Linux Server release 6.1 (Santiago)

3) List the available packages and specially the kernel version. Limit yum to use the new repository only.

yum --disablerepo="*" --enablerepo="server64x64" list available

yum --disablerepo="*" --enablerepo="server64x64" list kernel

4) Run the update command and wait it for completion.

For interactive mode, when questions have to be answered to proceed with the update, use:

yum --disablerepo="*" --enablerepo="server64x64" update

For automated mode, assuming all questions will be answered as “yes”, use:

yum –y --disablerepo="*" --enablerepo="server64x64" update

Example of what will be presented on the screen:

Transaction Summary

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

Install      21 Package(s)

Upgrade     278 Package(s)

Total download size: 224 M

Is this ok [y/N]:

Replaced:

  abrt-plugin-logger.x86_64 0:1.1.16-3.el6

  abrt-plugin-mailx.x86_64 0:1.1.16-3.el6

  abrt-plugin-rhtsupport.x86_64 0:1.1.16-3.el6

  abrt-plugin-sosreport.x86_64 0:1.1.16-3.el6

  libjpeg.x86_64 0:6b-46.el6

Complete!

5) Verify the new version of the OS

# uname -a

Linux SERVER1.domain.local 2.6.32-131.0.15.el6.x86_64 #1 SMP Tue May 10 15:42:40 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux

#cat /etc/redhat-release

Red Hat Enterprise Linux Server release 6.4 (Santiago)

6) Reboot to finish the process and to allow the new kernel and configuration be activated.

PS: RHEL 6.4 ships samba version 3.6. It has different configuration parameters in /etc/samba/smb.conf file when doing authentication thru AD.

Below are the required changes:

Before:

;    idmap uid = 10000-20000

;    idmap gid = 10000-20000

;    idmap backend = rid:DOMAIN=10000-20000

After:

    idmap config * : backend = tdb

    idmap config * : range = 20001-30000

    idmap config DOMAIN : backend = rid

    idmap config DOMAIN : range = 10000-20000

    idmap config DOMAIN : base_rid = 0

(Replace DOMAIN with the short name of your domain name)

7) End