How to scan for new disk in Linux(Redhat) without rebooting?.......................TIA.

I'll adding new disk from the EMC SAN and I am wondering if it's possible to
able to
mount the new disk without rebooting. So far fdisk or sfdisk will not see the
newly presented disk with a reboot.

You can unload and load the HBA driver which will cause it to rescan
the SCSI devices:
$$ modprobe -r hba-driver-module
$$ modprobe hba-driver-module

For example if you have a qlogic 2300 hba:
$$ modprobe -r qla2300
$$ modprobe qla2300

Also take a look at the following for a slightly less disruptive
approach:
http://www.garloff.de/kurt/linux/scsidev/

Cheers,
Vinay

Did you use
echo "scsi add-single-device hostadapter channel ID LUN"
/proc/scsi/scsi
? That should do it.

Ralf-Peter

On Tue, Dec 14, 2004 at 04:09:38PM -0800, RPR wrote:
Did you use
echo "scsi add-single-device hostadapter channel ID LUN"
/proc/scsi/scsi
? That should do it.

In Versions Linux 2.6 that's racy and may crash your machine,
especially if it's under heavy SCSI I/O load.

In Versions Linux 2.6 that's racy and may crash your machine,
especially if it's under heavy SCSI I/O load.

How to do this in Windows - probably will be interesting for somebody.

On NT4, just run WINDISK (Disk Administrator), it rescans all SCSI/IDE busses
on startup.

On w2k and later, go to Device Manager and say "Scan For Hardware Changes". Or
download the free DEVCON.EXE tool from www.microsoft.com to do the same from
command line.

Nothing racy.

Detaching the disk devices. Impossible on NT4, Device Manager/Disable or Device
Manager/Uninstall (or DEVCON) on w2k and later. Note that if dismount of the
filesystems on this disk fails due to open files on them, then Windows will
suggest you to reboot immediately - such a funny feature of the Device Manager
UI . You can neglect to reboot, but, on next reboot, the disk will be
disabled.

The rest of the detach procedure depends on your hardware.

--
Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation

http://www.storagecraft.com

BTW, why do you think you would be able to unload the driver module when it is busy ?

wrote:
You can unload and load the HBA driver which will cause it to rescan
the SCSI devices:
$$ modprobe -r hba-driver-module
$$ modprobe hba-driver-module

For example if you have a qlogic 2300 hba:
$$ modprobe -r qla2300
$$ modprobe qla2300

Also take a look at the following for a slightly less disruptive
approach:
http://www.garloff.de/kurt/linux/scsidev/

Cheers,
Vinay

A bunch of vendors recommend doing it this way:

http://download.qlogic.com/drivers/2...X-v7.01.01.txt

quote
When adding logical drives to the storage subsystem with the
SMclient
you will need to unload the device driver and then modprobe the
driver
to scan the new logical drives.
/quote

http://www-03.ibm.com/support/techdo...dex/FLASH10321

(PS: I'm not saying that this is the best way in the world to do this)
Cheers,
Vinay

"Christoph Hellwig" wrote in message
...
On Tue, Dec 14, 2004 at 04:09:38PM -0800, RPR wrote:
Did you use
echo "scsi add-single-device hostadapter channel ID LUN"
/proc/scsi/scsi
? That should do it.

In Versions Linux 2.6 that's racy and may crash your machine,
especially if it's under heavy SCSI I/O load.


It has also not been very reliable. It does not seem to work for adding new
LUNs to an existing target, something you will end up doing in a SAN
environment. In fact depending on the driver it may never work. I could not
even get the emulex driver to add new targets or LUNs, same for the Qlogic
cards. This is something I hope would be fixed in the 2.6 kernel. Most
modern operating systems supprot dynamic device reconfiguration (without
unloading the hba driver). Solaris, AIX, HP-UX, Dynix, Windows 200x all have
this feature.

-Don

unloading the hba driver). Solaris, AIX, HP-UX, Dynix, Windows 200x all have
this feature.

NT4 can dynamically load new HBA drivers and detect new devices, but cannot
handle removal.

--
Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation

http://www.storagecraft.com

Funny, I am currently fighting DS4300 connected to pair of Qlogic 2312 HBAs...
What a coincidence !
As for the topic, would not scsiadd do the job ?
I never tried it on FC hardware, but it always worked fine for regular SCSI devices.


wrote:

A bunch of vendors recommend doing it this way:

http://download.qlogic.com/drivers/2...X-v7.01.01.txt

quote
When adding logical drives to the storage subsystem with the
SMclient
you will need to unload the device driver and then modprobe the
driver
to scan the new logical drives.
/quote

http://www-03.ibm.com/support/techdo...dex/FLASH10321

(PS: I'm not saying that this is the best way in the world to do this)
Cheers,
Vinay