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GNU tar (Tape ARchive)

GNU tar (Tape ARchive) saves multiple files together into a single tape or disk archive, and can restore individual files from the archive. Here are some Linux tar Command with Useful Practical Examples

Some useful command line switches are given below, which are used in this article.

c => create an archive file. v => […]

GPG file encryption command line in Linux

GPG file encryption using key pair GPG basic file encryption doesn’t required public/private key. But to make a encrypted file more secure you can use RSA/DSA algorithms. These algorithms generates public and private keys to encrypt file.

There are three criteria to use GPG file encryption.

1. Encrypt/Decrypt file locally for same user account. 2. […]

Configure Caching Name Server on CentOS 6

Configure Caching Name Server on CentOS 6

A caching only DNS server caches DNS query results for the domain name being queried. These chache are stored for pre specified time known as the TTL ( time-to-live )

Step 1: Install the BIND Packages using Yum

Install bind packages using below command. In CentOS/RHEL 6 chaching-nameserver […]

Check DNS Configuration file ( BIND )

named-checkconf checks the syntax only of a named ( bind ) configuration file. The file is parsed and checked for syntax errors, along with all files included by it. If there are no file is specified with command, /etc/named.conf is read by default.

Tip 1: Check your dns ( bind ) configuration .

In case […]

Master Slave DNS Server on CentOS 6 and RHEL

How to Setup Master Slave DNS Server on CentOS 6 and RHEL

The DNS ( Domain Name System ) is a distributed system, used for transalate domain names to IP and vice a versa. This article will help you to How to Setup Master Slave DNS Server on CentOS 6 and RHEL Systems.

Network Scenario […]

“tuned” on RHEL/CentOS/Fedora

Starting with RHEL 6 ( and thus also with CentOS 6 ) Red Hat users have possibility to use tuned tool which gives possibility to activate different tuned profiles for RHEL 6 running server.

So what is tuned? ‘yum info tuned’ gives below

# yum info tuned

Description : The tuned package contains a […]

Tuning the Apache Prefork MPM

Apache uses a set of values called the Prefork MPM to determine how many servers it will utilize and how many threads each server can process. Out of the box all Apache installations use the same values regardless of whether your server has 512Mb of RAM or 8Gb of RAM.  It is important that as […]

jvm opts

+AdjustConcurrency +AggressiveOpts +AllowJNIEnvProxy +AllowParallelDefineClass +AllowUserSignalHandlers +AlwaysActAsServerClassMachine +AlwaysCompileLoopMethods +AlwaysLockClassLoader +AlwaysPreTouch +AlwaysRestoreFPU +AlwaysTenure +AnonymousClasses +AssertOnSuspendWaitFailure +BackgroundCompilation +BeParanoid +BindGCTaskThreadsToCPUs +BlockLayoutByFrequency +BlockLayoutRotateLoops +BlockOffsetArrayUseUnallocatedBlock +BranchOnRegister +BytecodeVerificationLocal +BytecodeVerificationRemote +C1OptimizeVirtualCallProfiling +C1ProfileBranches +C1ProfileCalls +C1ProfileCheckcasts +C1ProfileInlinedCalls +C1ProfileVirtualCalls +C1UpdateMethodData +CICompilerCountPerCPU +CITime +CMSAbortSemantics +CMSClassUnloadingEnabled +CMSCleanOnEnter +CMSCompactWhenClearAllSoftRefs +CMSConcurrentMTEnabled +CMSDumpAtPromotionFailure +CMSExtrapolateSweep +CMSIncrementalMode +CMSIncrementalPacing +CMSLoopWarn +CMSOldPLABResizeQuicker +CMSPLABRecordAlways +CMSParallelRemarkEnabled +CMSParallelSurvivorRemarkEnabled +CMSPermGenPrecleaningEnabled +CMSPrecleanRefLists1 +CMSPrecleanRefLists2 +CMSPrecleanSurvivors1 +CMSPrecleanSurvivors2 +CMSPrecleaningEnabled +CMSPrintChunksInDump +CMSPrintObjectsInDump +CMSReplenishIntermediate […]

JVM

JVM parameters set whether you know, here and share with you, including JVMHeap regional distribution, JVM’s two GC threads and Stack set and several other parts, I believe that this introduction to your study will be helpful.

Detailed JVM parameter settings

JVMHeap regional distribution:

JavaHeap is divided into three zones, Young, Old and Permanent. Young […]

Java tunning

The general tuning guidelines for java VM. Here are some general tunning guideline to help you categorize the kinds of java tunning you will perform: 1. Be aware of ergonomics settings The -server: server compiler The -XX:+useParallelGC: parallel garbage collector The -Xms: initial heap size is 1/64th of the machine’s physical memory The -Xmx: maximum […]

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