July 1, 2015
Networking Basics
CCNA workbook,What is a Network? A network is any collection of independent computers(devices) which are connected to one another to share files and peripherals such as printers, modems, tape drives. Every Network includes: At least two computer server or client work station Network Interface card(NIC) A connection medium(wired or wireless) Network Operating System software Protocols: Protocols…
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June 18, 2015
Iperf
Linux General,Iperf was developed by NLANR/DAST as a modern alternative for measuring maximum TCP and UDP bandwidth performance. Iperf allows the tuning of various parameters and UDP characteristics. Iperf reports bandwidth, delay jitter, datagram loss. Iperf is available also for Windows The quality of a link can be tested as follows: – Latency (response time or…
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June 2, 2015
MySQLTuner-perl Script
Linux General,MySQLTuner is a script written in Perl that allows you to review a MySQL installation quickly and make adjustments to increase performance and stability. The current configuration variables and status data is retrieved and presented in a brief format along with some basic performance suggestions. Compatibility: MySQL 3.23, 4.0, 4.1, 5.0, 5.1 (full support) MySQL…
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May 25, 2015
Linux – Creating a Partition Size Larger Than 2TB using Parted Command
Linux General,Find Out Current Disk Size: fdisk -l /dev/sdb Disk /dev/sdb: 3000.6 GB, 3000592982016 bytes 255 heads, 63 sectors/track, 364801 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/sdb doesn’t contain a valid…
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May 12, 2015
Add multiple interface and IP address – ubuntu and centos
Linux General,The below script uses to add bulk IPs for the same gateway and subnet : Save IPs in a file like /opt/dummy.txt and run the script to add them up. Interface add script – Ubuntu or Centos: echo Enter Distribution ubuntu\/centos read os if [ “$os” == “centos” ] then echo Enter Interface Name read…
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April 30, 2015
MEGACLI Commands to check Hardware RAID config and Setup
Linux General,To know the Hardware RAID controller and other information use the lspci command. lspci | grep -i raid O/P: 01:00.0 RAID bus controller: LSI Logic / Symbios Logic MegaRAID SAS 2108 [Liberator] (rev 05) The above command shows the RAID controller vendor details. Installation of Megacli in Centos: Download the MeGaCLIzip from the below link:http://www.lsi.com/downloads/Public/RAID…
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April 28, 2015
Migrating emails from one server to another without Server access
Mail Servers,Imapcopy: There are many tools available for this mail to mail migration, here we are going to use “Imapcopy”, which I believe to be the best and easy command line tool. It does support both Imap and Imaps protocols. Since this tool only uses ‘imap’ protocol to copy emails, not much of server resources will…
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March 11, 2015
Device eth0 does not seem to be present
VMware,Issues After restoring a VM from datastore or after cloning a centos VM on Vsphere, we see the following error during network restart “Device eth0 does not seem to be present” Cause: After cloning or restore from datastore, the MAC address needs to be edited on the VM configuration settings since the MAC ID tends…
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March 10, 2015
Vmware – Unable to operate a ESX host with locked disk
VMware,Background – No operation can be performed on an ESX host and you may see files are locked by other processes. Solution Determine which ESXi/ESX host has a locked or rogue file. * First login to the local tech support mode console on the host. * Use the command vmkfstools to obtain the lockstatus of…
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February 10, 2015
Integrating Parallels Virtuozzo container in Citrix Xen server
Linux General,We are trying to install virtuozzo 4.7 in a virtual Machine that has got centos running on it. Virtuozzo installation in this VM goes fine and the VM prompts for reboot post installation. During boot operation, the VM console freezes with lot of errors whereas you can still login to the Virtual machine using putty…
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