Simon Krenger

So one might want to ask why you’d want to sacrifice the fantastic stability and openness of Debian to install a vanilla (= original) kernel (Debian currently has 2.6.32). There are quite a few reasons for doing so. For example, the current kernel (2.6.38) has TRIM support, which is something I am looking for when using SSDs. Also, maybe you want to have a bleeding edge kernel just for the fun of it. So lets get started.

First order of business is to download a few packages, download the latest kernel from kernel.org and then unpack the kernel in /usr/src/:

While discussing the topic of cloud computing today, my co-worker mentioned the Amazon EC2 service and gave me a quick presentation of the features that are available. Since I am a big fan of virtualisation and the idea of scalable architectures, I immediately thought “This could be great to test some things out and is a wonderful opportunity to play around with different virtual machines”. So I signed up and did some quick tests to look at the IO performance…

I was especially interested in using these machines for storage and maybe some tests with databases. For these tests, my current Virtual Server serves as a reference, simply because EC2 could provide an alternative to that Virtual Server. In my tests, I included the following configurations:

One of the first things I do when I install PuTTY on a new machine, is to change the default color settings to something that is easier to read. This is a problem I have noticed on Red Hat machines, where the terminal color settings are not that great.

When you do an “ls” for example and the output contains folders, these are shown in a dark blue color, which makes it very hard to read on a black background. See the first picture in the gallery below.

Using Red Hat with Samba (Version 3.0.10-1.4E.11), I had the problem that Windows Explorer would not refresh properly when browsing the folders served by Samba. When creating a new folder, nothing showed up and it was necessary to manually refresh the Explorer window to see the “New Folder”. The same symptoms appeared with newly created files.

To fix this, add the following line to the [global] section of your smb.conf (usually located under /etc/samba/smb.conf):

[global]
refresh = 1

Sadly, I could not find this parameter in the official Samba manpages. Should anyone have more information or any documentation on this, feel free to let me know.

When I was installing Red Hat Enterprise Linux on a server, the machine suddenly hung at the following line:

PCI: Probing PCI Hardware (Bus 00)

This is a well-known problem (as a simple search on Google will reveal), so to solve it simply add the following parameter to the kernel boot configuration:

Well, you’ve got to go with the time. krenger.ch is now reachable through IPv6 thanks to the IPv6 support of HostEurope:

simon@atlas:~$ ping6 www.krenger.ch
PING www.krenger.ch(2a01:488:66:1000:53a9:2967:0:1) 56 data bytes
64 bytes from 2a01:488:66:1000:53a9:2967:0:1: icmp_seq=1 ttl=64 time=0.022 ms
64 bytes from 2a01:488:66:1000:53a9:2967:0:1: icmp_seq=2 ttl=64 time=0.035 ms
64 bytes from 2a01:488:66:1000:53a9:2967:0:1: icmp_seq=3 ttl=64 time=0.042 ms

For a startup script, I needed to start JBoss and start another component as soon as the complete JBoss server was started. When you execute the “run.sh” script that comes with JBoss, it immediately exits and starts JBoss in the background (which is quite nice I think). Unfortunately, when I started the other component using this method, the additional program was unhappy, since JBoss was not ready yet. So I had to come up with a trick to delay the start of the additional program.

So with the help of the internet and my co-worker, we came up with the following script:

Coming from Linux distributions where BASH is usually already set up and configured, I had to find my way around in a UNIX environment first. So here I present the files necessary for a proper installation of BASH under Solaris 10 (yes, I know Solaris 11 Express is out :)).

So after installing the BASH package (see my other post on setting up Solaris), you might find your new shell to be kinda boring. Also, it simply shows up as bash-3.00#, which by itself does not tell you a lot. So lets improve it a bit.

Out of curiosity, I decided to run the IOzone tests I performed with a RAID 10 (see this post) on a RAID-Z and compare it to the RAID 5 of the hardware RAID controller. For this test, I am using IOzone and two older HP DL380 G2 servers.

As I am currently fiddling around with Oracle Solaris and the related technologies, I wanted to see how the ZFS file system compares to a hardware RAID Controller. The ZFS file system allows you to configure different RAID levels such as RAID 0, 1, 10, 5, 6. In this post, I want to test the RAID 10 performance of ZFS against the performance with the HP RAID Controller (also in a RAID 10 configuration) over 4 disks.