megamap

MegaRAID™ Linux drive mapper

Usage

Run the megamap script and it will produce a map of MegaRAID drive ID to Linux drive sd* and also displays the WWN from Linux.

Requirements

• you need the megacli tool which needs to be run as root
• Readonly Perl module (debian package libreadonly-perl)

Usage

megamap takes no arguments and outputs a table of drive mappings such as:

$ sudo megamap
0       sdc     0x5000cca02ab9e1a0
1       sdf     0x5000cca02ab9b548
2       sde     0x5000cca02ab9bad0
3       sdd     0x5000cca02ab9b928
4       sdh     0x5000cca02ab9b5e8
5       sdg     0x5000cca02ab9b86c
6       sdj     0x5000cca02ab9b8c0
7       sdi     0x5000cca02ab9dde8
8       sdn     0x5000cca02ab9b34c
9       sdk     0x5000cca02ab9e7d8
10      sdl     0x5000cca02ab9e0c0
11      sdm     0x5000cca02ab9b350

megablink takes arguments of linux drives like /dev/sda or without the full path such as sdb and starts that drive blinking. Unblinking happens when the drive is replaced automatically, but there is also a megaunblink in case you accidentally blink the wrong drive. megablink -u also unblinks a drive.

$ sudo ./megablink /dev/sdn
blinking drive 8 (sdn), running megacli -PdLocate -start -physdrv[0:8] -a0
                                 
Adapter: 0: Device at EnclId-0 SlotId-8  -- PD Locate Start Command was successfully sent to Firmware 

Exit Code: 0x00

Notes

• 🌁 the Linux WWN is off-by-one or a few from what megacli shows.
• 👏 thanks to http://serverfault.com/questions/381177/megacli-get-the-dev-sd-device-name-for-a-logical-drive/ for getting me to look in /dev/disk/by-id
• 👏 thanks to http://www.network-administrator.co.uk/?p=575 for providing a handy reference to the megacli command structure
• 🐍 lsidrivemap is similar to megamap, but written in python and it has a nice table output format that shows the layout of the drives on the front of the server.
• 👏 thanks to Harry Lee for providing my first bug report and testing my eventual fix. It is really 🍩 great to know one person is using my project.

Debug Mode

If you set the MEGAMAP_DEBUG environment variable it won't run megacli or ls directly, but instead it will pull the data out of static files /tmp/megacli.out and /tmp/ls.out. If everything is working properly you should be able to generate those files like so:

megacli -pdlist -a0 | egrep 'Slot|^SAS' > /tmp/megacli.out
ls -l /dev/disk/by-id | grep -v part > /tmp/ls.out

Ideas

• docs in POD
• verify that it works on a system with more than 26 attached drives (the author does not currently have access to such a system)
• support multiple adapters through command line arguments or environment variables