Re: Adding a new FC disk to a linux host

[Steven Dake <sdake@mvista.com>]

There is a patch (search sourceforge for scsiras) that will 
automatically issue a rescan on the scsi bus whenever a reset occurs. 
 This won't help for fibrechannel, but you might be able to have your 
driver issue a reset causing the scsi bus to rescan with this modified 
kernel patch.

But I'd stick to just inserting what you know it out there rather then 
rescanning all 255 targets.

Thanks
-steve

Suresh Kr N wrote:

>This works for me ( by the way is this still BETA ? i dont see this comment
>in the kernel scsi sources anymore ).
>But then i need to deduce the these input parameters of target no , lun no
>etc , as i need to do this from a userland san management app.
>
>I figured that the HBA apis give you the new target number , and probably i
>could do a report luns or something to get the lun numbers as well. So this
>way could work for me .
>
>Is there a way to ask the midlayer for a full rescan ( so that i wont have
>to find out these parameters )
>
>suresh
>
>
>-----Original Message-----
>From: linux-scsi-owner@vger.kernel.org
>[mailto:linux-scsi-owner@vger.kernel.org]On Behalf Of Steven Dake
>Sent: Thursday, February 13, 2003 5:05 AM
>To: Suresh Kr N
>Cc: linux-scsi@vger.kernel.org
>Subject: Re: Adding a new FC disk to a linux host
>
>
>you can scan specific scsi ids.  read scsi_proc.c search for
>add-single-device
>
>         * Usage: echo "scsi add-single-device 0 1 2 3" >/proc/scsi/scsi
>         * with  "0 1 2 3" replaced by your "Host Channel Id Lun".
>         * Consider this feature BETA.
>
>
>Good luck
>-steve
>
>Suresh Kr N wrote:
>
>  
>
>>sorry about the wrong thread name in the previous post. updated now
>>
>>
>>hi everyone
>>
>>I am working on a san management application for a linux. My application
>>sends zoning commands to the fabric to zone in a disk to a host ,  so i
>>    
>>
>need
>  
>
>>to have that disk acessible to the host without a reboot of the host.
>>
>>I need to do this from the user space. Is there a way to ask the scsi
>>midlayer for a rescan ?
>>In solaris , i invoke a command called "drvconfig" to achieve this.
>>
>>I have seen in the linux-scsi archive that this is kind of possible,  but
>>the discussion didnt seem to state how.
>>I am attaching the above thread here in the mail.
>>
>>I have verified that echo "scsi add-single-device a b c d" >
>>    
>>
>/proc/scsi/scsi
>  
>
>>works fine . But this does involve parameters which cant be found out
>>programmatically.
>>
>>Also a side question here :In a FC world, to get the target number for
>>    
>>
>above
>  
>
>>command , can i find out the current maximum target number of the scsi
>>devices, and increase it by one ? or  does the FC devices have actually a
>>preknown target no , which would be collected by the FC card driver ?
>>
>>Could someone please help ? ( even a "non-standard" way should be good
>>enough" )
>>
>>Thanks
>>Suresh
>>
>>
>>
>>--------------------------------------------------------
>>Message 2 in thread
>>From: Alan Cox (alan@lxorguk.ukuu.org.uk)
>>Subject: Re: Hot plugging a disk in runtime
>>View this article only
>>Newsgroups: mlist.linux.scsi
>>Date: 2002-05-20 05:32:38 PST
>>
>>
>>
>>
>>    
>>
>>>1.. How is it possible to signal SCSI mid-layer (or other layers) of a
>>>presence of a newly hot-plugged disk ?
>>>
>>>
>>>      
>>>
>>aacraid is one example that does this, but via its config tools.
>>
>>
>>
>>    
>>
>>>2.. Can an adapter's device driver trigger SCSI subsystem to scan
>>>channels for new LUNs / Targets ?
>>>
>>>
>>>      
>>>
>>It is designed so user space can do so - so yes
>>
>>
>>
>>    
>>
>>>3.. Is this can be handled in a kernel level ? is there a user space
>>>application that can be triggered to start scanning adapters (obviously
>>>through SCSI subsystem) and registering new LUNs / Targets etc... ?
>>>
>>>
>>>      
>>>
>>echo "scsi-add-single-device a b c d" /proc/scsi/scsi
>>
>>if I remember it right
>>
>>
>>entire thread is at
>>
>>http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&threadm=linux.scsi.20020
>>    
>>
>5
>  
>
>>201420.g4KEK3x01892%40localhost.localdomain&rnum=7&prev=/groups%3Fq%3Dhot%2
>>    
>>
>B
>  
>
>>plug%2B%2BSCSI%2Bfibre-channel%2BLinux%26hl%3Den%26lr%3D%26ie%3DUTF-8%26sel
>>    
>>
>m
>  
>
>>%3Dlinux.scsi.200205201420.g4KEK3x01892%2540localhost.localdomain%26rnum%3D
>>    
>>
>7
>  
>
>>-
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>>
>>
>>    
>>
>
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