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254 - CUPS shared printer configuration

All you need to make this work are a central Linux/CUPS printer server, and one Linux PC per subnet to act as a relay printer server.

You have two subnets, and You need to have routing already configured to pass traffic between the two subnets,
so everyone can ping everyone. So you have your CUPS printer server at, and you want computers on to be able to use it.
This is a complete, barebones example CUPS configuration for

1. Print Server ( configuration

253 - How to install Apache Solr 3.6 for Drupal 7

Solr is the popular, blazing fast open source enterprise search platform from the Apache Lucene project.
Its major features include powerful full-text search, hit highlighting, faceted search, dynamic clustering,
database integration, rich document (e.g., Word, PDF) handling, and geospatial search. Solr is highly
scalable, providing distributed search and index replication, and it powers the search and navigation
features of many of the world's largest internet sites.

1. Install Java


252 - CUPS Spool Management

You have the spool directory of your Linux print subsystem.

For CUPS it is normally "/var/spool/cups/", as set by the cupsd.conf  directive "RequestRoot /var/spool/cups".

After printing, the job History & job file reside in /var/spool/cups. If you do not need them, you could clear them to make a room for CUPS.
So there are some parameters on CUPS to contorol them.

1. Print Job Files

251 - iSCSI target in /etc/tgt/targets.conf

< Create the targets >

Targets can be created by adding an XML entry to the /etc/tgt/targets.conf file, using our favorite text editor.
The target attribute requires an iSCSI Qualified Name (IQN).

Format :


yyyy-mm represents the 4-digit year and 2-digit month the device was started (for example: 2011-07)

250 - Change the default kernel that boots from GRUB

If you selected GRUB as your boot loader, you need to modify the file /boot/grub/grub.conf.

* default 0

The first menu entry title linux is the one to boot by default. grub.conf "default=x" getting updated upon yum update

To get changed it to "default=1".

Rebooting the machine boots to an old version of the kernel, rather than the new version which had been correctly loaded
as the 0th stanza in grub.conf.  Installing a new kernel RPM will insert a stanza into grub.conf for the new kernel version.



249 - Oracle PSU and CPU

1. PSU’s(Patch set updates) are patch sets but with some major differences with respect to regular patch sets.

PSUs are referenced by their 5th place in the Oracle version numbers which makes it easier to track ( (e.g. and will not change
the version of oracle binaries (like sqlplus, exp/imp etc.) As of now (10.2, 11,2) , the best way to  determine the PSU version installed  is
to use opatch utility using the command below.


248 - Use SNMP, snmpwalk

SNMP is a unified protocol of network monitoring and network device management. All active network devices support SNMP.
Besides that, SNMP is supported by major operational systems and a large number of network applications.

To install snmpwalk or snmpget on Redhat use the command yum install net-snmp-utils.


247 - ORA-27102: out of memory Linux-x86_64 Error

When trying to increase the SGA to approach half available RAM with an Oracle 64-bit
version on a Linux 64-bit operating system, even though shmmax is set to match half the amount of RAM,
you get the following error when trying to start the instance :

SQL> startup nomount

ORA-27102: out of memory
Linux-x86_64 Error: 28: No space left on device Changes


246 - RMAN compression feature

When using the RMAN compression feature, you can choose among different compression algorithms.
You can query the view V$RMAN_COMPRESSION_ALGORITHM to view the compression algorithms available to you, as shown here :


245 - du command

The du command is used to summarize disk usage of each file in a file system, recursively for directories.

# du -s /var/log/* | sort -nr | head -5

# du -s ./* | sort -nr | head -5




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