An amazing hot swap drive tray

I’m constantly playing around with Operating Systems and applications, and in the vast majority of cases I can use VirtualBox, KVM or VMWare to accomplish my testing. But in some cases I need to use physical hardware, which used to require me to shuffle drives and cables around in my custom built rack mount servers. Well, no more. I picked up a couple of SNT hot swap drive trays and now I can easily swap drives in and out of my rack mount servers. In addition to be being crazy useful, they also look cool:


To add a new drive you open the door, slide it in and then move the lock to the left to keep the drive in place. I couldn’t be happier with this set up, and the testing I did this morning would have taken me a LONG time if this nifty little device wasn’t in place. When you combine these with a solid case, you have a pretty killer home lab. What other solutions do folks use? USB drives? External disks? Something else?

Displaying CPU temperatures on Linux hosts

Intel and AMD keep coming out with bigger and faster CPUs. Each time I upgrade (I’m currently eyeing one of these) to a newer CPU it seems like the heat sinks and cooling fans have tripled in size (I ran across this first hand when I purchased a Zalman CPU cooler last year). If you use Linux and a relatively recent motherboard, there should be a set of sensors on the motherboard that you can retrieve the current temperatures from. To access these sensors you will first need to install the lm_sensors package:

$ yum install lm_sensors

Once the software is installed and configured for your hardware you can run the sensors tool to display the current temperatures:

$ sensors

Adapter: PCI adapter
Core0 Temp:
Core1 Temp:

This is useful information, especially if you are encountering unexplained reboots. Elevated temperatures can lead to all sorts of issues, and lm_sensors is a great tool for helping to isolate these types of problems. Now back to drooling over the latest generation of processors from Intel and AMD. :)

The easiest way to test the memory in your Intel-based PC!

Most admins have a series of tools they use to check for faulty hardware. This toolkit most likely includes the ultimate boot disk, a network accessible memtest and on a USB stick. I was always curious why Linux disitrubtions didn’t integrate these items into their install / live CDs, since it would make debugging flakey hardware a whole lot easier. Well, I was pleasantly surprised this week when I booted the Fedora 14 installation DVD and saw the following screen:


Once I selected the memory test option I was thrown directly into memtest:


This is solid, since one CD can now be used to test the memory in a server and repair things that go south. The Fedora 14 CD can be downloaded from the Fedora project website, and it’s definitely something that every Fedora admin should burn and store in a readily accessible location.

ARM vs. Intel Atom comparison

Van Smith wrote an awesome article comparing current ARM processors and their lower power consuming x86 friends such as the Intel Atom.

Here’s the conclusion of his performance benchmark tests:

The ARM Cortex-A8 achieves surprisingly competitive performance across many integer-based benchmarks while consuming power at levels far below the most energy miserly x86 CPU, the Intel Atom. In fact, the ARM Cortex-A8 matched or even beat the Intel Atom N450 across a significant number of our integer-based tests, especially when compensating for the Atom’s 25 percent clock speed advantage.

However, the ARM Cortex-A8 sample that we tested in the form of the Freescale i.MX515 lived in an ecosystem that was not competitive with the x86 rivals in this comparison. The video subsystem is very limited. Memory support is a very slow 32-bit, DDR2-200MHz.

Languishing across all of the JavaScript benchmarks, the ARM Cortex-A8 was only one-third to one-half as fast as the x86 competition. However, this might partially be a result of the very slow memory subsystem that burdened the ARM core.

More troubling is the unacceptably poor double-precision floating-point throughput of the ARM Cortex-A8. While floating-point performance isn’t important to all tasks and is certainly not as important as integer performance, it cannot be ignored if ARM wants its products to successfully migrate upwards into traditional x86-dominated market spaces.

Server hardware is dirt cheap!

I just built a quad core AMD-based server that I plan to use as a storage host in my lab. The machine has the following configuration:

ASUS M2N-LR motherboard
AMD Opteron 1354 Budapest 2.2GHz Socket AM2 75W processor
8GD of 667MHZ DDR2 ECC memory
4 750GB Western Digital SATA II disk drives
SAMSUNG 22X DVD±R DVD Burner with LightScribe
Antec earthwatts EA500 500W Continuous Power
ARK 4U-500-CA Black 4U Rackmount Case
2 masscool 80MM fans
1 Scythe 120MM case fan
1 Emulex LP1000DC fibre channel adapter

Now that the machine has been up and working for a few days, all I can say is WOW! This machine is blazing fast, and the rack mount case I purchased is absolutely amazing. It is extremely well constructed, and has TONS of space for future expansion. This rig is able to run opensolaris and CentOS Linux, and I couldn’t be happier with my purchase. Everything cost just over $600 (NewEgg and eBay rock!), which I think is an incredible price for a machine with these specifications. This machine will be a great storage server once I get COMSTAR configured!

Using the ultimate boot disk to test hardware

I have been using the Ultime Boot Disk for the past few months to test x86 and X64 hardware. The disk contains numerous awesome utilities that can be used to test memory, disks and CPUs. The following packages come on the CD, and are four of my personal favorites:

Memtest86+ to test memory

Darik’s Boot and Nuke to securely erase data from a disk drive

CPU burn to test CPUs

PCI sniffer to identify the type of card in a system