Installing CentOS 7 on C240's, raid config

[Mythobeast]

I've gotten over the driver hump of the install, and can install a working operating system, but there's something that's leaving me scratching my head.

First, the basics:

Servers: UCS C240 M4SX

Package:  3.2(3a)C

SAS drives: 24

PCH drives: 2

OS to install: CentOS 7.4

The sensible thing to do is to install the OS on the PCH drives, RAID1, and use the SAS drives for storage. In the BIOS, the PCH drives have two modes: 1. ACHI, and 2. PCH RAID.

Unfortunately, the CentOS installer doesn't recognize the PCH drives in ACHI mode, nor will it recognize them in PCH RAID mode when a RAID is configured. What it will do is recognize them in PCH RAID mode without a RAID configured.

The only route I found to installing it was to install it with the BIOS set as PCH RAID, with no RAID drives configured, and tell CentOS to set them up as a software RAID. Unfortunately, the BIOS doesn't recognize them as boot devices in PCH RAID mode, so after the installation I had to shift the drives into ACHI mode.

I present this in the hopes that others find value in this. I didn't install any drivers before kicking off the install because I found that all of the relevant drivers already exist in the CentOS7-Everything.iso.

[Kirk J]

Greetings.

That is not the intended design, you should be able to use the created VD.

Looks like you might be bumping into: https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvf28422/?rfs=iqvred which issue I'm assuming also rolled up into CENTOS.

Redhat removed support /no longer included inbox driver for MegaSR as of 7.3, see https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/7.1_release_notes/known-issues-installation and search on BZ#1008348 .

If you check the https://ucshcltool.cloudapps.cisco.com/public/# and base the search on centos/RHEL 7.2 vs 7.3/7.4 you'll notice the absence of the MegaraidSR listed under SAS RAID for 7.3/7.4 but it is present for 7.2 and earlier.

Hoping to see an update for this at some point.

 For the M5 servers, the 2 rear drive bays which are now externally accessible, are wired to the 12Gb SAS raid card, eliminating the megaSR/software raid complications. UCSC-C240-M5SX

Thanks,

Kirk...