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rhel 5

How To: Upgrade Red Hat Enterprise Linux 5.3 to v5.4

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.
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Install Linux On Intel Xeon 7400 Dunnington

Dunnington is Intel's first multi-core CPU - features a single-die six- (or hexa) core design with three unified 3 MB L2 caches (resembling three merged 45 nm dual-core Wolfdale dies), and 96 KB L1 cache (Data) and 16 MB of L3 cache. It features 1066 MHz FSB, fits into the Tigerton's mPGA604 socket, and is compatible with the Caneland chipset. These processors support DDR2-1066 (533 MHz), and have a maximum TDP below 130 W. They are intended for blades and other stacked computer systems.

I've Sun Blade X6450 server for ERP application:

The four-socket Sun Blade X6450 server module features Intel Xeon processor 7000 series and up to 192 GB of memory. With 24 DIMM slots per server module, it gives you 50 percent more memory capacity than competing blade servers making it an ideal fit for virtualization and server consolidation, HPC, database and enterprise applications. Fill a Sun Blade 6048 chassis for a remarkable 11TFLOPS of peak performance and up to 1152 processing cores per rack.

Fig.01: Sun Blade X6450 Server Module showing the internals

Fig.01: Sun Blade X6450 Server Module showing the internals

I tried old RHEL version and it failed to work because of old kernel. So I called to Redhat support and they told me to use at least kernel 2.6.18-92.1.10 and above. The problem is my client do not have RHEL 5.2 media and License (server came with Solaris 10). So I asked my client to get RHEL 5.2. Unfortunately, their local software vendor was out of stock for RHEL software. It took 5 days to get software media kit.

Finally, I've installed it on Sun blade server. It is working fine now. I wish I knew about latest Intel Xeon 7400 support problem earlier. It may have saved some time, effort, traveling and money on my part. I should have gone though server datasheet. This server only works with RHEL version 4.7 or 5.2 (32/64 bit) and above.

Red Hat Enterprise Linux 5 IMPORTANT Security Update [ 4-Nov-2008 ]

Red Hat today released kernel updates to fix at least 15 security flaws in its core called Linux kernel. RHEL users can grab the latest updates from RHN website or by simply running yum update command. This update has been rated as having important security impact.
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Linux Support For Intel Core i7 (Nehalem) Processors

Latest version of Linux kernel does support the Intel Core i7 (Nehalem) processors. Nehalem (microarchitecture), developed by Intel Corporation, successor to the Intel Core microarchitecture. Nehalem is the largest change in Intel's system architecture since the introduction of the Pentium Pro. Nehalem is highly scalable with different components for different tasks.
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Install Linux on Fujitsu Siemens ESPRIMO E5720

I was trying to install Redhat ( RHEL 5) / CentOS 5 server on a Fujitsu Siemens ESPRIMO E5720 and got problem with the installer.

The base resolution for CentOS / RHEL Linux 5 is 800x600x32, which requires 2MB video memory. In order to boot or install Linux on the Fujitsu Siemens ESPRIMO E5720, set the reserved amount of video RAM to 8MB in BIOS.

You also need to add pci=nommconf parameter to grub.conf boot option file. While installing Linux on Fujitsu Siemens ESPRIMO E5720, you need to type the following at a boot prompt (excluding boot: word itself):
boot: linux pci=nommconf
Once server is installed, edit /etc/grub.conf or /boot/grub/grub.conf and append pci=nommconf at the end of kernel line:

title Red Hat Enterprise Linux Server (2.6.18-128.el5)
	root (hd0,0)
	kernel /vmlinuz-2.6.18-128.el5 ro root=LABEL=/ console=tty0 console=ttyS1,19200n8 pci=nommconf
	initrd /initrd-2.6.18-128.el5.img

CentOS / Red Hat Enterprise Linux 5.2 Poor NFS Performance and Solution

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.

NFS server crashed each and every time web server node tried to store a large file 20-100 MB each. Read performance was fine but write performance went to hell. Finally, I had to rollback the updates. Recently, while reading Red Hat site I came across the solution.

Updated kernel packages that fix various security issues and several bugs are now available for Red Hat Enterprise Linux 5:

* a 50-75% drop in NFS server rewrite performance, compared to Red Hat
Enterprise Linux 4.6, has been resolved.

After upgrading kernel on both server and client my issue resolved:
# yum update

dnsmasq Dns Cache Software Security Update To Fix DNS Spoofing Attacks

Red Hat has shipped a new version of its dnsmasq caching software to plug source UDP port bug. This could have made DNS spoofing attacks (CVE-2008-1447) easier. Dnsmasq is lightweight ultra fast dns cache server forwarder and DHCP server. It is designed to provide DNS and, optionally, DHCP, to a small network.

This update has been rated as having moderate security impact, to upgrade your software, type the following command:
# yum update

This software only available under RHEL 5 / CentOS Linux 5.x. If you are using Debian / Ubuntu Linux, enter:
# apt-get update
# apt-get upgrade