MegaCLI Cheat Sheet // Support Tools

Working with RAID controllers can be a daunting task, especially if you only need to do it occasionally. MegaCLI, a powerful command-line tool for managing RAID controllers and disks, can be particularly challenging due to its cryptic syntax. To simplify the process, I’ve compiled this cheat sheet of essential MegaCLI commands and tips for easy reference.

Installing MegaCLI

To install MegaCLI on a Debian-based system, use:

sudo apt-get install megacli

Common Parameters

Controller Syntax: `-aN`

Use this to specify the adapter ID.
Avoid using the ALL flag to prevent accidental changes across all controllers.

Physical Drive: `-PhysDrv [E:S]`

E: Enclosure ID
S: Slot number (starting at 0).
Retrieve enclosure and slot information with:

megacli -EncInfo -aALL

Virtual Drive: `-Lx`

Use to specify the virtual drive where x is a number starting at 0 or the string all.

Information Commands

Get Controller Information

Display adapter details:
```
megacli -AdpAllInfo -aALL
```
Show RAID configuration:
```
megacli -CfgDsply -aALL
```

Export event logs:

megacli -adpeventlog -getevents -f lsi-events.log -a0 -nolog

Common Operations

Replace a Drive

Set the drive offline:
```
megacli -PDOffline -PhysDrv[E:S] -aN
```

Mark the drive as missing:

megacli -PDMarkMissing -PhysDrv [E:S] -aN

Prepare for removal:
```
megacli -PDPrpRmv -PhysDrv [E:S] -aN
```

Replace the drive and assign it:

megacli -PdReplaceMissing -PhysDrv[E:S] -ArrayN -rowN -aN

Start the rebuild process:

megacli -PDRbld -Start -PhysDrv [E:S] -aN

Fix a “Foreign” Drive

Mark the drive as good:

megacli -PDMakeGood -PhysDrv [E:S] -aALL

Clear the foreign configuration:
```
megacli -CfgForeign -Clear -aALL
```

Disable the Alarm

If the alarm is causing unnecessary noise, turn it off:

megacli -AdpSetProp AlarmDsbl -aALL

Why This Matters

MegaCLI is a powerful yet complex tool, and knowing these commands can save you hours of frustration during critical maintenance tasks. Bookmark this cheat sheet for your next encounter with RAID management!

For more insights and tips, feel free to connect with me on LinkedIn, GitHub, or BlueSky.

Happy troubleshooting!