I'm trying to load CentOS 6.3 on a used server based on a Tyan Tomcat n3400b motherboard. The first 2 drives are configured as a RAID mirror in the BIOS and the remaining 4 drives are not configured but apparently still have RAID metadata on them. I hadn't yet figured out how to fix that but went ahead and loaded the OS on the mirrored set.
After pulling out a drive from the unused set, grub stopped at the grub prompt. I can find (hd0,0)/grub/grub.conf but when I cat it I get corruption with recognizable fragments. I can use setup (hd0) without issue but reboots keep dumping me at the grub prompt. I booted into the rescue environment of the minimal install CD and grub.conf looks just fine. It's only corrupt when I look at it from the grub boot environment. What could be going wrong?
It's quite likely a software RAID card and when the OS was installed it only installed grub on one of the hard disks, the one that it thought was primary. I've seen this happen with quite a few software cards. Each time the OS booted it would load a different hard disk as primary. If you can, try disabling RAID on it all together.
----- Original Message ----- | I'm trying to load CentOS 6.3 on a used server based on a Tyan Tomcat | n3400b motherboard. The first 2 drives are configured as a RAID | mirror in | the BIOS and the remaining 4 drives are not configured but apparently | still | have RAID metadata on them. I hadn't yet figured out how to fix that | but | went ahead and loaded the OS on the mirrored set. | | After pulling out a drive from the unused set, grub stopped at the | grub | prompt. I can find (hd0,0)/grub/grub.conf but when I cat it I get | corruption with recognizable fragments. I can use setup (hd0) without | issue | but reboots keep dumping me at the grub prompt. I booted into the | rescue | environment of the minimal install CD and grub.conf looks just fine. | It's | only corrupt when I look at it from the grub boot environment. What | could | be going wrong? | _______________________________________________ | CentOS mailing list | CentOS@centos.org | http://lists.centos.org/mailman/listinfo/centos |
--On Friday, December 14, 2012 10:53 PM -0800 "James A. Peltier" jpeltier@sfu.ca wrote:
It's quite likely a software RAID card and when the OS was installed it only installed grub on one of the hard disks, the one that it thought was primary. I've seen this happen with quite a few software cards. Each time the OS booted it would load a different hard disk as primary. If you can, try disabling RAID on it all together.
Thanks. I completely disabled the Nvidia RAID controller in the BIOS and that made the 6 drives appear normal. I then had to delete the RAID metadata from the last 4 drives with dd, as there's a bug in dmraid that computes the offset to the metadata wrong. (It reports the offset and length to the metadata in bytes, then tries to use the same numbers as records to clear the data.)
https://bugzilla.redhat.com/show_bug.cgi?id=734468
https://www.redhat.com/archives/dm-devel/2011-August/msg00121.html
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James A. Peltier -
Kenneth Porter