Drive Information : ================= ------------------------------------------------------------------------------- EID:Slt DID State DG Size Intf Med SED PI SeSz Model Sp ------------------------------------------------------------------------------- 8:1 7 Onln 0 465.25 GB SATA HDD N N 512B WDC WD5003ABYX-01WERA1 U 8:2 6 Onln 0 465.25 GB SATA HDD N N 512B WDC WD5003ABYX-01WERA1 U 8:3 5 Onln 0 465.25 GB SATA HDD N N 512B WDC WD5003ABYX-01WERA1 U

------------------------------------------------------------------------------- EID:Slt DID State DG Size Intf Med SED PI SeSz Model Sp ------------------------------------------------------------------------------- 8:1 7 Onln 0 465.25 GB SATA HDD N N 512B WDC WD5003ABYX-01WERA1 U 8:2 6 Onln 0 465.25 GB SATA HDD N N 512B WDC WD5003ABYX-01WERA1 U 8:3 5 Onln 0 465.25 GB SATA HDD N N 512B WDC WD5003ABYX-01WERA1 U

Controller = 0 Status = Success Description = Operation on foreign configuration Succeeded FOREIGN CONFIGURATION : ===================== ---------------------------------------- DG EID:Slot Type State Size NoVDs ---------------------------------------- F - Cac0 Frgn 223.062 GB 1 ---------------------------------------- NoVDs - Number of VDs in disk group|DG - Diskgroup Total foreign drive groups = 1

Recently I installed a server with a Supermicro SMC2108 RAID adapter, which is actually a LSI MegaRAID SAS 9260. LSI created a command line utility called MegaCLI for Linux to manage this adapter. You can download it from their support pages. The downloaded archive contains an RPM file. I installed mc and rpm on Debian with apt-get, and then extracted the MegaCli64 binary (for x86_64) to /usr/local/sbin, and the libsysfs.so.2.0.2 from the Lib_utils RPM to /opt/lsi/3rdpartylibs/x86_64/ (that’s the location where MegaCli64 looks for this library).

Here are some useful commands:

View information about the RAID adapter

For checking the firmware version, battery back-up unit presence, installed cache memory and the capabilities of the adapter:

# MegaCli64 -AdpAllInfo -aAll

View information about the battery backup-up unit state

# MegaCli64 -AdpBbuCmd -aAll

View information about virtual disks

Useful for checking RAID level, stripe size, cache policy and RAID state:

# MegaCli64 -LDInfo -Lall -aALL

View information about physical drives

# MegaCli64 -PDList -aALL

Patrol read

Patrol read is a feature which tries to discover disk error before it is too late and data is lost. By default it is done automatically (with a delay of 168 hours between different patrol reads) and will take up to 30% of IO resources.

To see information about the patrol read state and the delay between patrol read runs:
# MegaCli64 -AdpPR -Info -aALL

To find out the current patrol read rate, execute
# MegaCli64 -AdpGetProp PatrolReadRate -aALL

To reduce patrol read resource usage to 2% in order to minimize the performance impact:
# MegaCli64 -AdpSetProp PatrolReadRate 2 -aALL

To disable automatic patrol read:
# MegaCli64 -AdpPR -Dsbl -aALL

To start a manual patrol read scan:
# MegaCli64 -AdpPR -Start -aALL

To stop a patrol read scan:
# MegaCli64 -AdpPR -Stop -aALL

You could use the above commands to run patrol read in off-peak times.

Migrate from one RAID level to another

In this example, I migrate the virtual disk 0 from RAID level 6 to RAID 5, so that the disk space of one additional disk becomes available. The second command is used to make Linux detect the new size of the RAID disk.
# /usr/local/sbin/MegaCli64 -LDRecon -Start -r5 -L0 -a0 # echo 1 > /sys/block/sda/device/rescan

Create a new RAID 5 virtual disk from a set of new hard drives

First we need to now the enclosure and slot number of the hard drives we want to use for the new RAID disk. You can find them out by the first command. Then I add a virtual disk using RAID level 5, followed by the list of drives I want to use, specified by enclosure:slot syntax.
# MegaCli64 -PDList -aALL | egrep 'Adapter|Enclosure|Slot|Inquiry' # MegaCli64 -CfgLdAdd -r5'[252:5,252:6,252:7]' -a0

View reconstruction progress

When reconstructing a RAID array, you can check its progress with this command.
# MegaCli64 -LDRecon ShowProg L0 -a0

(replace L0 by L1 for the second virtual disk, and so on)

Configure write-cache to be disabled when battery is broken

# MegaCli64 -LDSetProp NoCachedBadBBU -LALL -aALL

Change physical disk cache policy

If your system is not connected to a UPS, you should disable the physical disk cache in order to prevent data loss.

# MegaCli -LDGetProp -DskCache -LAll -aALL

To enable it (only do this if you have a UPS and redundant power supplies):

# MegaCli -LDGetProp -DskCache -LAll -aALL

More information

http://ftzdomino.blogspot.com/2009/03/some-useful-megacli-commands.html
https://twiki.cern.ch/twiki/bin/view/FIOgroup/DiskRefPerc
http://hwraid.le-vert.net/wiki/LSIMegaRAIDSAS
http://kb.lsi.com/KnowledgebaseArticle16516.aspx

attr: Frederick’s Blog

nJoy 😉

Tag: RAID

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