Archive
Posts from 2009
Using the Linux parted utility to re-create a lost partition table
I ran into an issue last week where two nodes using shared storage lost the partition table on one of the storage devices they were accessing. This was extremely evident in the output from fdisk: Fortunately the system in question still had the /proc/partition data in tact, so I stashed that in a safe location and came up with a plan to re-recreate the partition tables using this data. Given the following /proc/partitions data for the device listed above: I can see that the device had two partion table entries, and the device was approximately 100GB in size. To re-create the partition tables, I used the parted mkpart command passing it the starting and ending sector numbers I wanted written to the partition table: Now you may be asking yourself where did I get the starting and ending sectors from…
$ read more →Creating Linux bridging / tap devices with tunctl and openvpn
The more and more I play around with KVM virtualization, the more I realize just how useful Linux bridging is. In the Linux bridging world, a bridge device simulates a multiport Ethernet switch. To connect to the switch, you create a tap device that simulates a port on that switch. Once you have bridging configured on your host, there are two prevalent ways of going about creating taps…
$ read more →Backing up your COMSTAR storage configuration
I have been playing around with the COMSTAR iSCSI and FC port providers for the past few months, and other than a number of problems with the emlxs driver, they appear to work pretty well. As I've been experimenting, I wanted to back up my configuration in case something happened to my server. COMSTAR uses SMF and the underlying block device to store configuration data, so you can use svccfg to backup the configuration: If you ever need to restore the configuration, you can attach the storage and run an import: COMSTAR has some serious potential, and I'm looking forward to seeing the project grow in 2010!
$ read more →Expanding VMWare guest storage and extending LVM volumes and ext3 file systems to use the new storage
One of my production vSphere virtual machines came close to running out of space this past week. Expanding guest storage with vSphere is a breeze, and I wanted to jot down my notes in this blog post. To expand the size of a virtual disk, you will need to open the virtual infrastructure client, right click your guest and click "Edit Settings". Once the virtual machine settings window opens, you will need to navigate to the disk that you want to expand…
$ read more →Keeping up to date with CentOS happenings
I just found out the folks in the CentOS community have a planet feed! If you are interested in keeping up to date with all things CentOS, you should add their feed to your RSS reader.
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