I am attempting to install CentOS 7 on an older SuperMicro H8QM8 motherboard (AIC-7902 SCSI controller,
aic7xxx kernel module) with 3 attached drives. The Adaptec SCSI bios recognizes the drives and they have each been low-level formatted via the SCSI bios.
On using the CentOS GUI install to configure the hard drive layout, the installer detects the SCSI devices as a single
mpath device (is this normal?), however there a comment on the single
sdc. I seem to be able to successfully set up a partition table on a drive, but (at this point) I'm not sure exactly which drive I'm working on.
After the system reboots, I get an error about not finding
/dev/centos/root and also not being able to find
/dev/by-uuid/blahblahblah and get dropped into the dracut shell. I am able to confirm that (at this point) the
dm_* modules are loaded via a
kmod list but don't see the various HD nodes that the boot sequence was looking for. In
/dev I see
/dev/sdc, but no more specific partition nodes (i.e.
/dev/sda1). I don't seem to have access to
fdisk at this point, so I can't see which SCSI drive has the partition table, however the log shows that "something" detected that
/dev/sda has 3 partitions.
So then I reboot with the CentOS 7 CD in rescue mode, and the rescue boot successfully detects and mounts all my partitions under
/mnt/sysimage. At this point, I can see that the parititon table, file systems, and installed files all went to
So there are a two sub-questions, but perhaps I don't quite know how the multipath works and it is just a single question:
Why are the 3 drives displayed as a single mpath device in the installer? In the installer, is there a way to address a single drive (e.g.
/dev/sda) instead of the mpath device as a "whole"?
Why can the installed system not find the parition table on
/dev/sda? What information can I use (perhaps from the dracut emergency prompt) to further debug?