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Thursday, 19 August 2010

Kickstart cant repartion disks with software raid (md0 etc) arrays

If you're using kickstart to repartion disks with software raid arrays on them, you may get errors of the type 'no boot partion defined - may be due to lack of space'. I found this on a Rocks v5.3 Cluster running Scientific Linux 5.5 = Red Hat Enterprise Linux (RHEL) 5.5. Although kickstart has a 'clearpart' option that is supposed to clear existing partitions, it doesn't seem to do the job properly.

Solution- brutal but effective, make sure you don't want to keep anything off the disk: In the kickstart pre-install script (in rocks, put it in /export/rocks/install/site-profiles/5.3/nodes/replace-partition.xml  in the <pre> section) do

dd if-/dev/zero of=/dev/sda bs=1k count=64
dd if-/dev/zero of=/dev/sdb bs=1k count=64

as required to zero the partition tables of all the disks. It's not really necessary to zero anywhere near this much of the disk, but it take no time and I like to be thorough!

I saw mention of zeroing the raid superblocks with mdadm --zero-superblock <partition> but that  didn't seem to do it for me.

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