Following the adoption of Btrfs and SquashFS in Linux 2.6.29, the kernel development team have once more integrated two new file systems into 2.6.30 in the form of NILFS and EXOFS. NILFS is a new log-structured file system that dramatically improves write performance.

Understanding the distinction between your shell types, profile files and shell rc files is important because when you apply modifications to your system you need to know where  to set variables in order to make sure that they can be initialized as expected.

Let's give a quick answer for this topic which covers the exact difference between the two shells.

When you login your system and see the command line prompt, it's a login shell, and it executes these files in order:

• /etc/profile
• ~/.bash_profile

Clamav should be the best anti-virus software for linux, it's widely used and frequently updated for security vulnerabilities. If your server allows some public groups to upload files or serves as mail server, it's highly recommended to have a good antivirus installed, so that every of the unknown files would be scanned, in order to get rid of any potential attacks.

This week Facebook should have completed its new photo storage system which is designed to reduce the social network's reliance on expensive proprietary solutions from NetApp and Akamai. The new large blob storage system, named Haystack, is a custom-built file system solution for the over 850 million photos uploaded to facebook each month (500 GB per day!). Haystack stores photo data inside 10 GB bucket with 1 MB of metadata for every GB stored. Metadata is guaranteed to be memory-resident, leading to one disk seek for each photo on average.

kernel: ata2: status=0x51 { DriveReady SeekComplete Error }
The root cause is not understood yet but cabling or drivers is suspected.
Suggested: Raise a vendor call for the cabling to be checked.

kernel: lost page write due to I/O error on sda5
Data loss has occurred due to I/O problems.
Suggested: Check the previous lines to identify the root cause

kernel: ata1: error=0x40 { UncorrectableError }

In a former post, we know that with the help of defrag_mem we can clean up buffers / cached memory to gain more real "free" memory. Defrag_mem works like common windows memory optimizer, it asks for as much memory as possible, and then free them all. This way is not suggested on productive servers unless you have no other choices.

An inode identifies a file and its attributes including size, owner, permissions, etc. Inode number is unique within a file system, to be specified, we can also call it partition.
Normaly, we use rm to delete files, is there any necessary to remove files by inode? I'd say yes there is!
On the common linux filesystem ext3, it's allowed to use control characters or characters which are unable to be input on a keyboard or special character such as ^, /, ?, * as a file name.

This article shows you some useful usage examples for netcat. Netcat is known as the TCP/IP swiss army knife.
From the netcat man page: netcat is a simple unix utility which reads and writes data across network connections, using TCP or UDP protocol. It is designed to be a reliable back-end tool that can be used directly or easily driven by other programs and scripts.

The first public release of bash-4.0 is now available here at GNU.org, and from the usual GNU mirror sites. Unlike previous bash distributions, this released file includes the formatted documentation (postscript, dvi, html, and nroffed versions of the manual pages). Diffs from bash-3.2 are not available.This is the fourth major release of bash. It fixes the remaining serious bugs in the bash version 3 branch and introduces significant new features.

wget is one of favorite tools in Linux/Unix world. Sometimes,
you want to download all the rpm, deb, iso, or tgz files and save them
into a directory. Sometimes you need to use it to check your web server status.