The sar command collects, report, or save UNIX / Linux system activity information. It will save selected counters in the operating system to the /var/log/sa/sadd file. From the collected data, you get lots of information about your server:
- CPU utilization
- Memory paging and its utilization
- Network I/O, and transfer statistics
- Process creation activity
- All block devices activity
- Interrupts/sec etc.
The sar command output can be used for identifying server bottlenecks. However, analyzing information provided by sar can be difficult, so use kSar tool. kSar takes sar command output and plots a nice easy to understand graph over a period of time.
Red Hat Enterprise Linux v5.4 has been released and available via RHN for immediate update. The new version includes the kernel-based virtual machine (KVM) virtualization, next generation of developer features and tools including GCC 4.4, a new malloc(). Also included clustered, high-availability filesystem to support Microsoft Windows storage needs on Red Hat Enterprise Linux.
Microsoft chief operating officer Kevin Turner recently talked about netbook and claimed that retailers experiencing higher return rates as compare to MS-Windows operating systems:
And the reason that we were able to make so much traction – because this is the first real test of the value of Windows – the reason we were able to make so much traction on this particular space is because we went to retailers and said, “Hey, what are your return rates on these Linux netbooks that you are getting?” And they said, “Oh, gosh, they’re, like, four or five times higher than what we’re seeing on other PCs that have Windows.” I said, “Exactly.” So let’s do the TCO story. Let’s talk to customers. And you can’t find a retailer – I challenge you to find a retailer who wants to sell Linux on these netbooks, because the returns are bad. The customer complaints are bad. And our ability to really showcase the value proposition with Windows has never been greater and was never tested more than it was with this particular product. But we’ve made great progress there, but the up-sell opportunities with Windows 7, because it runs so well on these low-end laptops, is going to be tremendous for us.
As a system admin, I need to use additional hard drives for to provide more storage space or to separate system data from user data. This procedure, adding physical block devices to virtualized guests, describes how to add a hard drive on the host to a virtualized guest using VMWare software running Linux as guest.
It is possible to add or remove a SCSI device explicitly, or to re-scan an entire SCSI bus without rebooting a running Linux VM guest. This how to is tested under Vmware Server and Vmware Workstation v6.0 (but should work with older version too). All instructions are tested on RHEL, Fedora, CentOS and Ubuntu Linux guest / hosts operating systems.
Research shows that if your web pages take longer than 5 seconds to load, you lose 50% of your viewers and sales. As a UNIX admin often end users and web developers complain about website loading speed and timings. Usually, there is nothing wrong with my servers or server farm. Fancy java script and images / flash makes site pretty slow. These tools are useful to debug performance problems for sys admins, developers and end users. Here are six tools that can analyzes web pages and tells you why they are slow. Use the following tools to:
- Make your site faster.
- Debug site problem, especially client side and server side stuff.
- Better user experience.
- Improve the web.
Google has announced Google Chrome OS, which should be available mid-2010. This is a direct challenge to MS Windows operating systems. This is excellent news and it is going to tied tightly to its Chrome Web browser. Google Chrome running within a new windowing system on top of a Linux kernel. Speed, simplicity and security are the key aspects of Google Chrome OS – said Sundar Pichai, VP Product Management, in a blog post.
A redundant array of inexpensive disks (RAID) allows high levels of storage reliability. RAID is not a backup solution. It is used to improve disk I/O (performance) and reliability of your server or workstation. A RAID can be deployed using both software and hardware. But the real question is whether you should use a hardware RAID solution or a software RAID solution.
In this post I will document my experience with both software and hardware RAID.
I‘ve Windows Vista installed as a guest under Ubuntu Linux using VMWARE Workstation 6.0. This is done for testing purpose and browsing a few site that only works with Internet Explorer. Since I only use it for testing I made 16GB for Vista and 5GB for CentOS and 5GB in size for FreeBSD guest operating systems. However, after some time I realized I’m running out of disk space under both CentOS and Vista. Adding a second hard drive under CentOS solved my problem as LVM was already in use. Unfortunately, I needed to double 32GB space without creating a new D: drive under Windows Vista. Here is a simple procedure to increase your Virtual machine’s disk capacity by resizing vmware vmdk file.
WARNING: This tutorial only works with older Linux kernels version such as 2.6.xx.
A typical question from my mailbag:
How do I find out if a given PCI hardware is supported of by the current CentOS / Debian / RHEL / Fedora Linux kernel?
You can easily find out find out if a given piece of PCI hardware such as RAID, network, sound, graphics card is supported or not by the current Linux kernel using the following utilities under any Linux distributions.
The Blue Screen of Death (BSoD) is used by Microsoft Windows, after encountering a critical system error. Linux / UNIX like operating system may get a kernel panic. It is just like BSoD. The BSoD and a kernel panic generated using a Machine Check Exception (MCE). MCE is nothing but feature of AMD / Intel 64 bit systems which is used to detect an unrecoverable hardware problem. MCE can detect:
- Communication error between CPU and motherboard.
- Memory error – ECC problems.
- CPU cache errors and so on.