How to remove scsi san disk?

[Ryan Golhar]

Ah ha.  It is because of multipathing.  I have two controllers on my SAN 
and they are both plugged in.  "scsi_id -g -s /dev/sdb" and "scsi_id -g 
-s /dev/sdc" report the same UUID.

Now, on to figure out multipathing...good article btw: 
http://www.dell.com/downloads/global/power/ps3q06-20060189-Michael.pdf



Ryan Golhar wrote:
> I was able to remove /dev/sdb and /dev/sdc.  I even went so far as to 
> remove the mapping from the SAN, rebooted and only the native hd is 
> picked up at /dev/sda.
> 
> I re-mapped a 500GB parition to this particular host...there is only one 
> fibre-channel card plugged in, the second one isn't used yet.  When I 
> rebooted/rescanned for drives, both /dev/sdb and /dev/sdc are picked up.
> 
> /dev/sdc is recognized as the 500GB parition, but linux can't read 
> /dev/sdb.  What is this and where is it coming from?  I'm not using 
> multipathing as far as I'm aware of.
> 
> oh the SAN is a Sun StorageTek 2540.
> 
> Ryan
> 
> 
> Ray Van Dolson wrote:
>> On Fri, Apr 17, 2009 at 10:06:49AM -0700, Ryan Golhar wrote:
>>> How do I determine the device mapping of a SCSI drive to the SCSI 
>>> host, bus, lun?  And  How to I remove the mapping to delete the SCSI 
>>> drive?
>>>
>>> I have a fibre-connected SAN.  I've created a few drives on the SAN 
>>> and mapped it to my linux host.  The linux host sees the drives just 
>>> fine. I remove the drives from linux, and left them as uninitialize 
>>> disks. Whenever I run "fdisk -l", I get output:
>>>
>>> [root at cicweb1 tmp]# /sbin/fdisk -l
>>>
>>> Disk /dev/sda: 440.0 GB, 440076861440 bytes
>>> 255 heads, 63 sectors/track, 53502 cylinders
>>> Units = cylinders of 16065 * 512 = 8225280 bytes
>>>
>>>     Device Boot      Start         End      Blocks   Id  System
>>> /dev/sda1   *           1          13      104391   83  Linux
>>> /dev/sda2              14       53502   429650392+  8e  Linux LVM
>>>
>>
>> This might help:
>>
>>   http://kbase.redhat.com/faq/docs/DOC-3942
>>
>> I typically use /proc/scsi/scsi or lsscsi to list the devices and
>> figure out which ones I want to remove, then use the appropriate
>> command to remove the device.
>>
>>> I also get in /var/log/messages that drives that I since removed from 
>>> the SAN.  How to I remove these (/dev/sdb and /dev/sdc) in linux?
>>
>> <snip>
>>
>> I wonder if you have multipathing set up?  The failover path often will
>> show up as an invalid or unavailable drive.
>>
>> This usually can be fixed by setting the correct multipath device
>> settings in your /etc/multipath.conf config file.
>>
>> Ray
>>