I have a few servers with hardware RAID directly on the motherboard. They’re not the best boards in the world, but they process my data and serve up the information I want. Recently, I noticed that one of the servers was running on the /dev/sdb* devices, which was extremely odd. Digging some more, it seemed that /dev/sda* existed and seemed to be ok, but wasn’t being used.
After some searching, I was able to determine that the server, when built, actually booted up on /dev/mapper/via_* devices, which were actually the hardware RAID. At some point these devices disappeared. To make matters worse, it seems that kernel updates weren’t being applied correctly. My guess is that either the grub update was failing, or it updated a boot loader somewhere that wasn’t actually being used to boot. As a result, an older kernel was loading, with no way to get to the newer kernel.
I spent some time tonight digging around with Google, posting messages on the CentOS forums, and digging around on the system itself. With guidance from a user via the forums, I discovered that my system should be using dmraid, which is a program that discovers and runs RAID devices such as the one I have. Digging around a bit more with dmraid and I found this :
[user@dev ~]$ sudo /sbin/dmraid -ay -v
Password:
INFO: via: version 2; format handler specified for version 0+1 only
INFO: via: version 2; format handler specified for version 0+1 only
RAID set “via_bfjibfadia” was not activated
[user@dev ~]$
Apparently my RAID is running version 2 and dmraid only supports versions 0 and 1. Since this was initially working, I’m at a loss as to why my RAID is suddenly not supported. I suppose I can rebuild the machine, again, and check, but the machine is about 60+ miles from me and I’d rather not have to migrate data anyway.
So how does one go about fixing such a problem? Is my RAID truly not supported? Why did it work when I built the system? What changed? If you know what I’m doing wrong, I’d love to hear from you… This one has me stumped. But fear not, when I have an answer, I’ll post a full writeup!