Technical - Spheron1

September 17, 2010

Dell PowerVault MD3000i balancing virtual disks between RAID controllers

The Dell PowerVault MD3000i iSCSI SAN has a pair of redundant RAID controller modules designed to maximise availability of the mission critical data held in your Storage Area Network. These RAID controller modules can work in a pseudo active/active mode through a bit of a work around, however there seems to be some confusion on the Dell mailing lists and...

Dell PowerVault/iSCSI Comments: 0

September 16, 2010

The dreaded scrolling GRUB GRUB GRUB on startup

Rebooting a server is always stressful, particularly when you don’t have immediate physical access to it. Of course, when the server inevitably doesn’t come back up you need to either get directly on the local console or connect in via KVMoIP and one of the worst things you can see is “GRUB GRUB GRUB” scrolling past endlessly. This is a...

Red Hat and CentOS Comments: 0

September 12, 2010

Python setuptools and get_python_version is not defined

If you run into the below error when using setuptools (setup.py), then it’s quite possible that you’re using an outdated version of Python’s setuptools. In particular, the python-setuptools package in the CentOS yum repository is too old. Traceback (most recent call last): File “setup.py”, line 19, in ? setup(**metadata) File “/usr/lib64/python2.4/distutils/core.py”, line 149, in setup dist.run_commands() File “/usr/lib64/python2.4/distutils/dist.py”, line 946,...

Red Hat and CentOS Comments: 0

August 16, 2010

Sysconfig ifcfg scripts and VLAN sub-interfaces

If you are using the ifcfg scripts in /etc/sysconfig/network-scripts to bring up VLAN sub-interfaces on a NIC and you are getting messages such as: Bringing up interface eth0.200: Device eth0.200 does not seem to be present, delaying initialization. instead of Bringing up interface eth0.200: Added VLAN with VID == 200 to IF -:eth0:- as you would expect, then make sure...

Red Hat and CentOS Comment: 1

August 16, 2010

HyperVM and yum update Transaction Check Errors

If you’re having file conflict problems when running “yum update” on servers with the lxlabsupdate repository for HyperVM (or Kloxo) installed then there’s a simple resolution: cd /var/cache/yum/lxlabsupdate/packages/ rpm -Uvh *.rpm –replacefiles –replacepkgs This should fix errors such as: file /usr/share/man/man1/pcregrep.1.gz from install of pcre-8.02-1.el5_5.1.x86_64 conflicts with file from package pcre-6.6-2.el5_1.7.i386 file /usr/share/man/man1/pcretest.1.gz from install of pcre-8.02-1.el5_5.1.x86_64 conflicts with file...

Red Hat and CentOS Comments: 0

July 18, 2010

Restoring the contents of /dev

Have you ever deleted everything out of /dev by accident (or even on purpose)? Although it may seem that all is lost or that you have a lot of work ahead of you, it’s actually quite easy to restore on a modern Linux system such as CentOS 5 (or the RHEL equivalent). The first thing you need to know is...

Red Hat and CentOS Comments: 0

July 4, 2010

SSH on a HP ProCurve

By default HP ProCurve devices (like most switches) use telnet and TFTP (Trivial File Transfer Protocol) for management access, firmware upgrades and config backups. As these are both unencrypted protocols, it is a good idea to switch to using SSH and SCP/SFTP in order to secure your management access and all important configuration, which you can do with the following...

HP ProCurve Comments: 0

July 3, 2010

Re-open an accidentally closed tab in Safari 5.0

Apple’s 5.0 release of the fantastic Safari web browser has introduced a feature I’ve been waiting for since discovering it several years ago in a somewhat unstable third party plugin who’s name escapes me and which has been in Firefox for some time – the ability to re-open an accidentally closed tab. When combined with the “Reopen Last Closed Window”...

Mac OS X Comment: 1

July 3, 2010

Changing the MAC address of a VLAN interface in Mikrotik RouterOS

Do you want to change the MAC address of a VLAN interface in Mikrotik RouterOS? Are you baffled by the fact that although the VLAN interface has a MAC address property inherited from the parent Ethernet interface, it isn’t editable? Well, you’re in luck, it isn’t actually impossible to give your VLAN interface a different MAC address to it’s parent...

Mikrotik RouterOS Comment: 1

June 19, 2010

Retrieve the Dell PowerEdge Service Tag remotely from Windows or Linux

Have you ever wanted to get the Dell Service Tag from a PowerEdge machine that you don’t have physical access to? Well it’s actually quite easy as Dell make this available through the standardised Desktop Management Interface (otherwise known as DMI) framework, so you don’t even have to install any of Dell’s OpenManage tools to view it! On a Linux...

Dell PowerEdge/Linux/Servers/Windows Comments: 0

Category: Technical

Dell PowerVault MD3000i balancing virtual disks between RAID controllers

The dreaded scrolling GRUB GRUB GRUB on startup

Python setuptools and get_python_version is not defined

Sysconfig ifcfg scripts and VLAN sub-interfaces

HyperVM and yum update Transaction Check Errors

Restoring the contents of /dev

SSH on a HP ProCurve

Re-open an accidentally closed tab in Safari 5.0

Changing the MAC address of a VLAN interface in Mikrotik RouterOS

Retrieve the Dell PowerEdge Service Tag remotely from Windows or Linux