# Detect new disk on LSI MegaRaid SCSI controller

## humbletech99

I have an linux server with an LSI MegaRaid 320-2X SCSI Controller. It works fine and I have a bunch of disks being used by the operating system so the card and driver works fine.

I have added some new disks, initialized them etc and the lsi management software can see the disks and regards them as online, but the operating system cannot see them

There is not much point in having a hot-swap controller if the operating system can't make use of of though.

Is there any way to force the operating system to see the new disks...?

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## Keruskerfuerst

fdisk -l should show the disks.

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## humbletech99

it does not of course because the kernel has not recognized the new drives yet...

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## rburcham

Do you (or does anyone) have a solution here yet?  I have a Dell PE 2850 with an attached PV 220S.  I have loaded up the array with physical disks and used dellmgr to configure & initialize two separate raid 5 logical drives (each 1.6 TB).

The megaraid driver is loaded and it scanned the controllers at boot time (when it had no logical drives configured), but I need it to see the new logical drives now.  I tried using rescan-scsi-bus, but while it sees all the hosts and channels, it does not see the new logical drives (or physical disks for that matter).  What's more it appears to put the drives into a "background initialization state..." that is, when I return to dellmgr and look at the logical drives, they appear to now be in this background initialization state, each with a progress bar that shows 0%, never advancing.

Clearly I am missing something.  Could someone instruct me on how to configure these drives such that the system can see them?  I know I don't have to reboot this production system, do I?

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## rburcham

Oh.... oh dear God....  I check the progress bars this morning after letting it run overnight... they show 1% complete... I have googled:

From http://www.rm.com/Support/TechnicalArticle.asp?cref=TEC521186

"Consistency checks run as background tasks and will take some time to complete. For example, a 500GB array will take about two days to complete. Running a check will have minimal impact on server performance and the server can continue to be used as normal."

So for my two volumes together it's going to take over a week to complete this consistency/background init check?  The article suggests that the volumes should be usable in this state, but I cannot get the system to see them and/or set up /dev devices for them.  When I run rescan-scsi-bus the volumes are not discovered, and returning to the megamgr/dellmgr utility shows the two logical volumes in this state.

I have not tried a reboot as this machine is serving users around the globe.  Don't really wanna do that unless I know it'll pay off.  Besides, the whole point of having hardware hot-swappable RAID is so you don't have to reboot, right?

Are there any LSI or PERC experts out there who can set me straight?

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## rburcham

So anyway, you can tell the driver to rescan by talking directly to /proc like so:

 *Quote:*   

> 
> 
> echo "scsi add-single-device host bus target lun" > /proc/scsi/scsi

 

Consequently, issuing

 *Quote:*   

> # echo "scsi add-single-device 1 2 0 0" > /proc/scsi/scsi
> 
> # echo "scsi add-single-device 1 2 1 0" > /proc/scsi/scsi

 

scored my 3.2 TB of disk.  Done and done.

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