Archive
Posts from 2009
Backing up and restoring partition tables on Linux hosts
I recently had to adjust the partition layout on a couple of disk drives. This work occurred on devices with actual data (I made backups before starting), so I needed to be extra careful while performing my work. To ensure that I could recover the data if something went wrong with the partitioning, I made backups of each partition prior to beginning work. Assuming you are using a DOS (MBR) labeled disk, there are two ways to back up the partition table: Use dd to archive sector 0 to a safe location Archive the partition table to a safe location with parted or sfdisk To backup a device using option 1, you can use a dd statement similar to the following: To restore the partion table using dd, you can can alter the dd source and destination like so: While this approach works well, I tend to prefer the second method…
$ read more →Using the Linux netconsole service to send console messages to remote hosts
Most Linux distributions ship with the netconsole service, which allows kernel printk() messages to be sent to a remote destination. This feature can be useful for debugging system hangs and panics, and is handy for archiving console messages to a central location. To configure netconsole, you will need to add the IP address of a remote syslog server to /etc/sysconfig/netconsole. Here is a sample entry: Once the IP is added to the configuration file, you can start the netconsole service: This will load the netconsole kernel module, and write the configuration that was used to the system logs: If the netconsole service starts up successfully, each console message should be routed to the remote syslog server…
$ read more →Great resource for managing djbdns servers
I am in the process of setting up a couple of caching DNS servers, and decided to test out djbdns (we used it at my last job with great success). While perusing the web, I came across the life with djbdns site. This site provides a thorough explanation of djbdns, and also covers configuration in detail. If you are interested in learning how djbdns works, this site is for you!
$ read more →Adding storage, network and 3rd party kernel modules to a Linux initrd image
While playing around with initrd images a few weeks back, I came across the mkinitrd "--with" option. This option allows you to add additional modules to an initrd image, which is useful when you have a new storage or Ethernet driver that isn't supported by the base operating system. To use this option, you can place the names of the modules to add to the initrd image in quotes, and pass them to the "--with" option: To verify the image contains the modules you specified, you can extract the initrd image and poke around the lib/modules directory: If you want the modules included in all future mkinitrd runs, you can add the modules to the modules variable in the/etc/sysconfig/initrd file. Nice!
$ read more →VMWare tools opensourced
I just came across the open vm tools website. The site hosts the source code to VMWare's vmtools package, and will be the future home for development surrounding this package. I have encountered a number of issues with vmtools in the past, and the fact that it was closed source made debugging problems difficult. This is exciting news!
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