http://www.cyberciti.biz/tips This is a Linux sys admin journal by Vivek about sys admin work, Linux tips & tricks, hacks, news and more. Wed, 24 Apr 2013 18:50:55 +0000 en-US hourly 1 http://wordpress.org/?v=3.5.1 http://www.cyberciti.biz/tips/open-source-project-management-software.html http://www.cyberciti.biz/tips/open-source-project-management-software.html#comments Sun, 19 Jul 2009 19:18:10 +0000 nixCraft http://www.cyberciti.biz/tips/?p=5477 Project management software is not just for managing software based project. It can be used for variety of other tasks too. The web-based software must provide tools for planning, organizing and managing resources to achieve project goals and objectives. A web-based project management software can be accessed through an intranet or WAN / LAN using a web browser. You don't have to install any other software on the system. The software can be easy of use with access control features (multi-user). I use project management software for all of our projects (for e.g. building a new cluster farm) for issue / bug-tracking, calender, gantt charts, email notification and much more.

Obviously I'm not the only user, the following open source software is used by some of the biggest research organizations and companies world wild. For e.g. NASA's Jet Propulsion Laboratory uses track software or open source project such as lighttpd / phpbb use redmine software to keep track of their projects.]]> http://www.cyberciti.biz/tips/open-source-project-management-software.html/feed 85 http://www.cyberciti.biz/tips/common-causes-of-downtime-in-datacenter.html http://www.cyberciti.biz/tips/common-causes-of-downtime-in-datacenter.html#comments Wed, 27 May 2009 14:42:27 +0000 nixCraft http://www.cyberciti.biz/tips/?p=4895 Unplanned downtime may be the result of a software bug, human error, equipment failure, power failure, and much more. Last week was a bad one. We faced three different downtime:

• First, there was a fiber cut for one of our data center resulting into routing anomalies due BGP reroute. Traffic was rerouted but updating those BGP tables took some time to update.
• Someone from networking team failed to follow proper maintenance procedures for network device resulted into 55 minutes downtime.
• One of our SAN hardware failure - Many internal UNIX / Linux web applications use SAN to store data including file server, tracking apps, R&D apps, IT help desk, LAN and WAN servers failed. This one lasted for 12 hrs. It was stared around midnight. The vendor replaced entire SAN hardware. Now we have dual stacked SAN as a backup device for internal usage.

Note: There is a poll embedded within this post, please visit the site to participate in this post's poll.]]> http://www.cyberciti.biz/tips/common-causes-of-downtime-in-datacenter.html/feed 6 http://www.cyberciti.biz/tips/linux-unix-bsd-mac-filtering.html http://www.cyberciti.biz/tips/linux-unix-bsd-mac-filtering.html#comments Tue, 17 Feb 2009 18:37:21 +0000 nixCraft http://www.cyberciti.biz/tips/?p=4452 MAC Filtering (layer 2 address filtering) refers to a security access control methodology whereby the 48-bit address assigned to each network card is used to determine access to the network. Iptables, pf, and IPFW can block a certain MAC address on a network, just like an IP. One can deny or allow from MAC address like 00:1e:2a:47:42:8d using open source firewalls. MAC address filtering is often used to secure LAN or wireless network / devices. Is this technique effective? ]]> http://www.cyberciti.biz/tips/linux-unix-bsd-mac-filtering.html/feed 14 http://www.cyberciti.biz/tips/multitail-view-multiple-files-like-tail-command.html http://www.cyberciti.biz/tips/multitail-view-multiple-files-like-tail-command.html#comments Mon, 09 Feb 2009 19:28:32 +0000 nixCraft http://www.cyberciti.biz/tips/?p=4399 tail is one of the best tool to view log files in a real time (tail -f /path/to/log.file). The program MultiTail lets you view one or multiple files like the original tail program. The difference is that it creates multiple windows on your console (with ncurses). This is one of those dream come true program for UNIX sys admin job. You can browse through several log files at once and do various operations like search for errors and much more.]]> http://www.cyberciti.biz/tips/multitail-view-multiple-files-like-tail-command.html/feed 13 http://www.cyberciti.biz/tips/bind-named-set-zone-transfer-ip-address.html http://www.cyberciti.biz/tips/bind-named-set-zone-transfer-ip-address.html#comments Thu, 08 Jan 2009 20:08:01 +0000 nixCraft http://www.cyberciti.biz/tips/?p=4277 I've three nameserver load-balanced (LB) in three geo locations. Each LB has a front end public IP address and two backend IP address (one for BIND and another for zone transfer) are assigned to actual bind 9 server running Linux. So when a zone transfer initiates from slave server, all I get errors. A connection cannot be established, it tries again with the servers main ip or LB2 / LB3 ip. This is a problem because my servers are geo located and load balanced. However, there is a small workaround for this problem.]]> http://www.cyberciti.biz/tips/bind-named-set-zone-transfer-ip-address.html/feed 4 http://www.cyberciti.biz/tips/howto-linux-boot-2tb-larger-raidarray-harddisk.html http://www.cyberciti.biz/tips/howto-linux-boot-2tb-larger-raidarray-harddisk.html#comments Thu, 04 Dec 2008 07:13:58 +0000 nixCraft http://www.cyberciti.biz/tips/?p=3718 I've already written about creating a partition size larger than 2TB under Linux using GNU parted command with GPT. In this tutorial, I will provide instructions for booting to a flat 2TB or larger RAID array under Linux using the GRUB boot loader.]]> http://www.cyberciti.biz/tips/howto-linux-boot-2tb-larger-raidarray-harddisk.html/feed 3 http://www.cyberciti.biz/tips/linux-swap-space.html http://www.cyberciti.biz/tips/linux-swap-space.html#comments Wed, 19 Nov 2008 08:50:49 +0000 nixCraft http://www.cyberciti.biz/tips/?p=3586 Linux and other Unix-like operating systems use the term "swap" to describe both the act of moving memory pages between RAM and disk, and the region of a disk the pages are stored on. It is common to use a whole partition of a hard disk for swapping. However, with the 2.6 Linux kernel, swap files are just as fast as swap partitions. Now, many admins (both Windows and Linux/UNIX) follow an old rule of thumb that your swap partition should be twice the size of your main system RAM. Let us say I've 32GB RAM, should I set swap space to 64 GB? Is 64 GB of swap space really required? How big should your Linux / UNIX swap space be? ]]> http://www.cyberciti.biz/tips/linux-swap-space.html/feed 64 http://www.cyberciti.biz/tips/linux-unix-parallel-nfs.html http://www.cyberciti.biz/tips/linux-unix-parallel-nfs.html#comments Thu, 13 Nov 2008 12:17:31 +0000 nixCraft http://www.cyberciti.biz/tips/?p=3519 NFS is pretty old file sharing technology for UNIX based system and storage systems. However, it suffers from performance issues. NFSv4.1 address data access issues by adding a new feature called parallel NFS (pNFS) - a method of introducing Data Access Parallelism. The end result is ultra fast file sharing for clusters and high availability configurations.

The Network File System (NFS) is a stalwart component of most modern local area networks (LANs). But NFS is inadequate for the demanding input- and output-intensive applications commonly found in high-performance computing -- or, at least it was. The newest revision of the NFS standard includes Parallel NFS (pNFS), a parallelized implementation of file sharing that multiplies transfer rates by orders of magnitude. ]]> http://www.cyberciti.biz/tips/linux-unix-parallel-nfs.html/feed 2 http://www.cyberciti.biz/tips/howto-setup-linux-iscsi-target-sanwith-tgt.html http://www.cyberciti.biz/tips/howto-setup-linux-iscsi-target-sanwith-tgt.html#comments Tue, 11 Nov 2008 02:39:48 +0000 nixCraft http://www.cyberciti.biz/tips/?p=3485 Linux target framework (tgt) aims to simplify various SCSI target driver (iSCSI, Fibre Channel, SRP, etc) creation and maintenance. The key goals are the clean integration into the scsi-mid layer and implementing a great portion of tgt in user space.
The developer of IET is also helping to develop Linux SCSI target framework (stgt) which looks like it might lead to an iSCSI target implementation with an upstream kernel component. iSCSI Target can be useful:

a] To setup stateless server / client (used in diskless setups).
b] Share disks and tape drives with remote client over LAN, Wan or the Internet.
c] Setup SAN - Storage array.
d] To setup loadbalanced webcluser using cluster aware Linux file system etc.

In this tutorial you will learn how to have a fully functional Linux iSCSI SAN using tgt framework.]]> http://www.cyberciti.biz/tips/howto-setup-linux-iscsi-target-sanwith-tgt.html/feed 26 http://www.cyberciti.biz/tips/seagates-barracuda-15tb-hard-disk.html http://www.cyberciti.biz/tips/seagates-barracuda-15tb-hard-disk.html#comments Tue, 21 Oct 2008 18:53:46 +0000 nixCraft http://www.cyberciti.biz/tips/?p=3149 Wow, this is a large size desktop hard disk for storing movies, tv shows, music / mp3s, and photos. You can also load multiple operating systems using vmware or other software for testing purpose. This hard disk comes with 5 year warranty and can transfer at 300MB/s. But, How reliable is the 1.5TB hard disk?]]> http://www.cyberciti.biz/tips/seagates-barracuda-15tb-hard-disk.html/feed 1 http://www.cyberciti.biz/tips/linux-kernel-intel-core-i7.html http://www.cyberciti.biz/tips/linux-kernel-intel-core-i7.html#comments Fri, 03 Oct 2008 20:20:11 +0000 nixCraft http://www.cyberciti.biz/tips/?p=3751 Linux support the Intel Core i7 (codenamed Nehalem) processors under latest kernel and CentOS 4.7 and 5.2]]> http://www.cyberciti.biz/tips/linux-kernel-intel-core-i7.html/feed 21 http://www.cyberciti.biz/tips/saving-electricity-for-data-center.html http://www.cyberciti.biz/tips/saving-electricity-for-data-center.html#comments Wed, 01 Oct 2008 20:05:07 +0000 nixCraft http://www.cyberciti.biz/tips/?p=3005 Learn from Google how to save electricity while serving millions of request across a globe. Google come up with 5-step approach to build efficient data centers.]]> http://www.cyberciti.biz/tips/saving-electricity-for-data-center.html/feed 2 http://www.cyberciti.biz/tips/centos-rhel-poor-nfs-write-performance.html http://www.cyberciti.biz/tips/centos-rhel-poor-nfs-write-performance.html#comments Fri, 22 Aug 2008 09:41:58 +0000 nixCraft http://www.cyberciti.biz/tips/?p=2759 A few days ago I noticed that NFS performance between a web server node and NFS server went down by 50%. NFS was optimized and the only thing was updated Red Hat kernel v5.2. I also noticed same trend on CentOS 5.2 64 bit edition.]]> http://www.cyberciti.biz/tips/centos-rhel-poor-nfs-write-performance.html/feed 4 http://www.cyberciti.biz/tips/rhel-linux4-setup-device-mapper-multipathing-devicemapper.html http://www.cyberciti.biz/tips/rhel-linux4-setup-device-mapper-multipathing-devicemapper.html#comments Sun, 06 Jul 2008 06:06:29 +0000 nixCraft http://www.cyberciti.biz/tips/?p=3707 http://www.cyberciti.biz/tips/rhel-linux4-setup-device-mapper-multipathing-devicemapper.html/feed 2 http://www.cyberciti.biz/tips/linux-backing-up-large-files.html http://www.cyberciti.biz/tips/linux-backing-up-large-files.html#comments Mon, 30 Jun 2008 09:04:59 +0000 nixCraft http://www.cyberciti.biz/tips/?p=2425 http://www.cyberciti.biz/tips/linux-backing-up-large-files.html/feed 2 http://www.cyberciti.biz/tips/linux-reduces-average-power-consumption.html http://www.cyberciti.biz/tips/linux-reduces-average-power-consumption.html#comments Tue, 10 Jun 2008 12:13:17 +0000 nixCraft http://www.cyberciti.biz/tips/?p=2357 http://www.cyberciti.biz/tips/linux-reduces-average-power-consumption.html/feed 3 http://www.cyberciti.biz/tips/amazoncom-web-site-service-unavailable.html http://www.cyberciti.biz/tips/amazoncom-web-site-service-unavailable.html#comments Fri, 06 Jun 2008 18:33:23 +0000 nixCraft http://www.cyberciti.biz/tips/?p=2349 http://www.cyberciti.biz/tips/amazoncom-web-site-service-unavailable.html/feed 5 http://www.cyberciti.biz/tips/linux-set-io-scheduling-class-priority.html http://www.cyberciti.biz/tips/linux-set-io-scheduling-class-priority.html#comments Tue, 03 Jun 2008 13:13:44 +0000 nixCraft http://www.cyberciti.biz/tips/?p=2339 Describes how to deal with high disk I/O generating scripts or programs using ionice and CFQ scheduling class under Linux.]]> http://www.cyberciti.biz/tips/linux-set-io-scheduling-class-priority.html/feed 11 http://www.cyberciti.biz/tips/google-data-center-information.html http://www.cyberciti.biz/tips/google-data-center-information.html#comments Sat, 31 May 2008 09:43:42 +0000 nixCraft http://www.cyberciti.biz/tips/?p=2334 http://www.cyberciti.biz/tips/google-data-center-information.html/feed 1 http://www.cyberciti.biz/tips/consistent-backup-linux-logical-volume-manager-snapshots.html http://www.cyberciti.biz/tips/consistent-backup-linux-logical-volume-manager-snapshots.html#comments Wed, 31 May 2006 19:13:58 +0000 nixCraft http://www.cyberciti.biz/tips/consistent-backup-with-linux-logical-volume-manager-lvm-snapshots.html LVM is an implementation of a logical volume manager for the Linux kernel. The biggest advantage is that LVM provides the ability to make a snapshot of any logical volume.]]> http://www.cyberciti.biz/tips/consistent-backup-linux-logical-volume-manager-snapshots.html/feed 12