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Red Hat Cluster Suite

October 30th, 2011

Sanjib

In today’s world, every organisation in is thriving to provide a nonstop 24X7 service to their clients and so deploying high available solutions to their products. This is where a cluster concept kicks in. Along with some commercial high-availability solutions like IBM’s HACMP and Veritas’ Cluster Server and HP’s Serviceguard, Red Hat provides a high-availability solution on Red Hat Enterprise Linux, called the Red Hat Cluster Suite.

Red Hat Cluster Suite has two major features, the Cluster Manager ( Cman) that provides high availability, and the IP load balancing (also called Piranha). The Cluster Manager and Piranha are complementary high-availability technologies and can be used in combination or separately, as per your requirements. (more…)

Posted in General, Open Source, Tips and Tricks

Tags: availability technologies, Block device, bond0 master device, bonding, ccs, Classes of computers, Cluster, Cluster computing, cluster infrastructure, cluster management, Cluster manager, cluster services, cluster solutions, CLVM, clvmd services, cman, Computing, data integrity, Distributed Lock Manager, DLM, DNS, Environment, Ethernet, ethernet bonding, Ethernet channel, Fencing, fencing device, GFS, Global File System, Grand Unified Lock Manager, gui, GULM, hardware fence devices, High availability, high-availability technologies, IP load balancing, Linux, linux bonding, Load balancing, lock management, lock manager, manager for GFS, Parallel computing, Piranha, Piranha Ventures Inc., power switch, Red Hat, Red Hat Cluster Suite, redhat cluster suite, redundancy, RHCS, SAN, server-based lock manager, standalone server, Technology/Internet, virtual device

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Logical Volume manager (LVM)

October 29th, 2011

Sanjib

Using the Logical Volume Manager or LVM we can create special kind of volumes to store datas which can be increased or decreased as per need. This resizing of the volumes are of minimal effort and so comes handy for managing the resources effectively. The following diagram will give you a better understanding of how the LVM works

Let us consider there are two HDD of 10 GB each ( /dev/sda and /dev/sdb). We can create physical partitions of 5 GB in both the disks( /dev/sda1 , /dev/sda2, /dev/sdb1, /dev/sdb2). Now picking three of these partitions we create one volume group ( we can later include new hdd or the remaining 5 Gb partition to the volume group ) of 15 GB. Now we can create smaller logical volumes as per need from this available 15GB space. Lets consider we have created one logical volume of 8 Gb. So there is still 7 Gb of space in hold. We can use this space to make more Logical volumes of use it when the already created LV needs resizing. (more…)

Posted in General, Open Source, Tips and Tricks

Tags: +devices, cluster lvm, Computer storage, Computing, create lvm, Device file system, Disk file systems, extend lvm, File system, Linux, logical volume group, Logical volume management, Logical Volume Manager, lvcreate, lvdisplay, LVM, lvm cluster, lvreduce, lvremove, lvscan, physical volume, pvcreate, pvdisplay, pvscan, remove, resize2fs, shrink volume, Storage, vgcreate, vgdisplay, vgscan, Volume, Volume group, XFS

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NFS – Network File System

October 28th, 2011

Sanjib

Network File System (NFS) is a way to share files between machines on a network as if the files are located on the client’s local hard drive. It is an effective way to share files to a group of users using the same network. e.g. a group of users are working on a project and needs to share their files stored in a particular directory. In such a case, everyone can upload/share their files in a common folder( like /project) and share it over NFS.

For the NFS service, one ( any RedHat machine with the package installed) machine in a system works as a server while others can connect to it to fetch/share files. Sharing files from an NFS server is known as exporting the directories. A X-Windows based application is available to edit the configuration file, but since in the previous post ( OD Hardening), I already mentioned that generally X Windows is not needed in production server and should be removed, I will discuss the procedure to edit the configuration file using text editors. (more…)

Posted in General, Open Source, Tips and Tricks

Tags: Computer networking, Computing, File locking, File system, firewall, Internet protocols, Network File System, Network file systems, NFS, NFS server, Portmap, protmap, recovery services, Remote procedure call, remote systems, Rlogin, rpc.lockd, rpc.mountd, Security, Technology/Internet, UDP, WebNFS

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Linux systems – monitoring

October 27th, 2011

Sanjib

Monitoring a system is an essential part of system administration and a regular monitoring/checking will only make sure that everything is in order. There are several things to monitor in a server, viz user accounts, CPU or memory loads and network traffics.

We will start with the user accounts. In the previous post I have already discussed about the security issues related to user accounts and the reason a good password policy is required and how to implement it. Also how to check if an user is trying to use incorrect password to login or attempting for su privilege. A few basic commands to monitor user accounts are : (more…)

Posted in General, Open Source, Tips and Tricks

Tags: Central Processing Unit, Computing, CPU, Daemon, Delete user, delete username, few more effective tools, Filesystem Hierarchy Standard, Linux, loads, lock user, lock username, memory, monitoring, network traffics, Password, password policy, remove user, remove username, sar, sar command, SCSI, strong password, Su, Sudo, systat, System administration, system administrator, system monitor, System software, Technology/Internet, top, unlock user, unlock username, User, user administration, user monitor, Virtual memory

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Securing and Hardening Red Hat Linux

October 26th, 2011

Sanjib

Securing or Hardening a system is one of the primary tasks for any system administrator. A lot many things can be tweaked to make your system secure and I will point out a few of the standard baseline to make a linux box secure. I will not cover services or applications like Apache or Samba or Squid etc., since these are not needed for all linux systems. Also, security features requiring kernel patching is not covered. (more…)

Posted in General, Open Source, Tips and Tricks

Tags: Close unwanted Ports, disable root login, failed login, Hardening, Linux, listening ports, lock accounts, network monitor, OS, package removal, password ageing, password policy, patch management, patching linux system, Red Hat Runlevel System Services, Secure Shell, secure ssh, securing, Security, ssh, strong password, up2date, update

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Archive for October, 2011

Red Hat Cluster Suite

Logical Volume manager (LVM)

NFS – Network File System

Linux systems – monitoring

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