April 2015


April 2015

LVM2: device filter and LVM metadata restore

LVM2: device filter and LVM metadata restore Customize LVM device filter to get rid of the annoying “/dev/cdrom: open failed” warning

##/dev/cdrom: open failed warning $pvcreate /dev/sdb1 /dev/cdrom: open failed: Read-only file system $ vgcreate vg01 /dev/sdb1 /dev/cdrom: open failed: Read-only file system ##The error because LVM scan all device files by default, you can […]

How to mount LVM partitions from rescue mode (Fedora/CentOS/RedHat)

Boot your rescue media. Scan for volume groups: # lvm vgscan -v

Activate all volume groups: # lvm vgchange -a y

List logical volumes: # lvm lvs –all

With this information, and the volumes activated, you should be able to mount the volumes: # mount /dev/volumegroup/logicalvolume /mountpoint

Fix ShellShock Bash Vulnerability

With the announcement of the ShellShock Bash vulnerability last week it has caught news around the security updates. This is bug is being dubbed to be bigger than The Heartbleed Bug. Some interesting read about ShellShock can be found here.

Fix ShellShock Bash Vulnerability on CentOS – Test

Before you begin it’s better to test […]

Solved mount: special device /dev/VolGroup00/LogVol00 does not exist

Solved mount: special device /dev/VolGroup00/LogVol00 does not exist

There are times when using LVM you might come accross the error while mounting an LVM partition. The error that we are discussing here is mount: special device /dev/VolGroup00/LogVol00 does not exist.

[root@rmohan ~]# mount /dev/VolGroup00/LogVol00 /media/data


mount: special device /dev/VolGroup00/LogVol00 does not exist

Maybe in […]

Start/Stop/Delete a Queue Manager

Start/Stop/Delete a Queue Manager

Starting a Queue Manager

Before we can use a Queue Manager, we need to start it, using the STRMQM command. The command to start a Queue Manager called QMA is:

$ strmqm QMA

You should see output similar to the following on your screen:

WebSphere MQ queue manager ‘QMA’ starting.

2108 […]

DoS and DDoS attacks

Short definition : In computing, a denial-of-service attack (DoS attack) or distributed denial-of-service attack (DDoS attack) is an attempt to make a machine or network resource unavailable to its intended users. Odli?an link.

How to detect them # netstat -ntu | awk ‘{print $5}’ |awk -F: ‘{print $(NF-1)}’| sort | uniq -c | sort -n|grep […]

GPG on Linux

GNU Privacy Guard (GnuPG or GPG) is a GPL Licensed alternative to the PGP suite of cryptographic software. GnuPG is compliant with RFC 4880, which is the current IETF standards track specification of OpenPGP. Current versions of PGP (and Veridis’ Filecrypt) are interoperable with GnuPG and other OpenPGP-compliant systems.

Solution 1 – Encrypt with a […]

Weblogic Monitoring Dashboard to monitor the resources

Monitoring dashboard is the new feature of latest weblogic server to view diagnostic data without doing additional setup.

This is the extension of the WLDF framework. The Monitoring Dashboard provides views and tools for graphically presenting diagnostic data about servers and applications running on them. The underlying functionality for generating, retrieving, and persisting diagnostic data […]

Changing the weblogic server admin console timeouts.

The console application can be find at the below location $WEBLOGIC_HOME\server\lib\consoleapp

Change the directory location to $WEBLOGIC_HOME/server/lib/consoleapp/webapp/WEB-INF and open the weblogic.xml in a text editor.

Look for a session param tag with the name as “invalidation-interval-secs” and “timeout-secs”

Default Values

<session-descriptor> <timeout-secs>3600</timeout-secs> <invalidation-interval-secs>60</invalidation-interval-secs> <cookie-name>ADMINCONSOLESESSION</cookie-name> <cookie-max-age-secs>-1</cookie-max-age-secs> <url-rewriting-enabled>false</url-rewriting-enabled> </session-descriptor>

Change the value for “invalidation-interval-secs” and “timeout-secs” as […]

Weblogic Managed server status struck in STARTING

We faced the issue while starting the weblogic managed server the status of the server struck in STARTING.

W could not able to find a valid error messages in the log files

Managed Server Log File:

<30-Oct-2013 11:13:29 o’clock GMT> <Notice> <WebLogicServer> <BEA-000365> <Server state changed to STARTING>

No logs are getting printed after […]