Wednesday, August 26, 2015

Checking the RAID level with MegaCLI on Ubuntu 14.04

I recently installed Ubuntu 14.04 on a new PC (Dell Precision Tower 7910) and wanted to check the RAID configuration that the system had been set up to use. Unfortunately none of the BIOS or system configuration menus seemed to give me access to this information.

Luckily a colleague pointed me towards MegaCLI, a utility for obtaining information about (and troubleshooting) LSI RAID controllers. Instructions on how to install and use MegaCLI are given in this Nerdy Notes blog post: However as this dates from 2012, doesn't cover use on Ubuntu, and doesn't include information on how to interpret the outputs from the utility, I've written up what I did below.

0. Check you're using a MegaRAID controller

Directly from Nerdy Notes: do

lspci -nn | grep RAID

and check that the output for MegaRAID, e.g.

02:00.0 RAID bus controller [0104]: LSI Logic / Symbios Logic MegaRAID SAS-3 3008 [Fury] [1000:005f] (rev 02)

1. Obtain and install MegaCLI

The first problem is actually obtaining a copy of MegaCLI. According to the Nerdy Notes post, it should be available for download by searching on the LSI website, however when I tried this the download link was non-functional. Subsequently I've discovered that it can be located by searching on the Avago site (go to and enter "megacli" into the search box).

Opening the downloaded zip file reveals a set of subdirectories with versions of the utility for different OSes, with the Linux directory only holding a "noarch" RPM file. This should be straightforward to install using yum on Redhat-based systems (such as Fedora), but for Ubuntu it's necessary to extract the MegaCLI executables using the rpm2cpio utility:

rpm2cpio MegaCli-8.07.14-1.noarch.rpm | cpio -dimv

(The rpm2cpio utility can be installed via the rpm2cpio package using Synaptic or apt-get.)

This should pull out the MegaCli64 executable. Note that it doesn't need to be installed in any special location, you can run it from wherever you extracted it to using the above command, however you need to run with superuser privileges otherwise the output is blank.

2. Run MegaCli6 to probe the RAID information

To get information on the adapter and see which RAID levels the system supports, do:

sudo MegaCli64 -AdpAllInfo -aAll

and grep the output for "RAID"; this should give you output of the following form:

RAID Level Supported            : RAID0, RAID1, RAID5, RAID00, RAID10, RAID50, PRL 11, PRL 11 with spanning, SRL 3 supported, PRL11-RLQ0 DDF layout with no span, PRL11-RLQ0 DDF layout with span

Then to get information on which RAID level is actually being used:

sudo MegaCli64 -LDInfo -Lall -aAll

and again grep for "RAID":

RAID Level          : Primary-5, Secondary-0, RAID Level Qualifier-3

This doesn't explicitly name a "standard" RAID level, but I found this ServerFault post which gives details on how to interpret the output:

In this case "Primary-5, Secondary-0, RAID Level Qualifier-3" turns out to be equivalent to RAID 5
(, which is suitable for my needs - so I was able to rest a bit easier.

I'd like to acknowledge my colleague Ian Donaldson for tipping me off about MegaCLI.

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