CentOS - Dec 2007 - Qlogic HBA scanning issues with CentOS 5.1 ?

Hi,

I got few servers (IBM HS20,HS21 blades, IBM xSeries 3650 & others) 
connected to a dual fabric san throught Qlogic HBA's (23xx, 24xx). 
Multipathing is done with device-mapper-multipath.

On CentOS 4.x i can scan for new scsi devices without any problems, get 
them up with multipathing & use them without any problems.

However, after i started installing CentOS 5.1 (did not notice this 
problem with CentOS 5) i cannot seem to rescan without huge problems. 
Sometimes when i rescan after presenting a new LUN to the server nothing 
is detected, and sometimes the device comes in without any problems at 
all. Sometimes i even loose some paths after rescanning.....again, i had 
no problems at all with CentOS 4.x.

I use the Qlogic script (Dynamic Target and LUN Discovery 
<http://support.qlogic.com/support/EULATemplate/Template.aspx?TemplateID=9&path=http://download.qlogic.com/ms/56614/ql-dynamic-tgt-lun-disc-2.2.tgz>
2.2) to scan for new luns.

Has anyone had any issues with scanning for new devices off san after 
upgrading to 5.1 ?

Thanks,
Finnur

On Fri, 2007-12-14 at 21:55 +0000, Finnur ?rn Gu?mundsson
wrote:
> Hi,
> 
> I got few servers (IBM HS20,HS21 blades, IBM xSeries 3650 & others) 
> connected to a dual fabric san throught Qlogic HBA's (23xx, 24xx). 
> Multipathing is done with device-mapper-multipath.
I've installed the same machines on several IBM DS3xxx or DS4xxx SANs
but i used the provided rdac multipath driver (adviced by IBM in their
documentation)
> 
> On CentOS 4.x i can scan for new scsi devices without any problems, get 
> them up with multipathing & use them without any problems.
> 
> However, after i started installing CentOS 5.1 (did not notice this 
> problem with CentOS 5) i cannot seem to rescan without huge problems. 
> Sometimes when i rescan after presenting a new LUN to the server nothing 
> is detected, and sometimes the device comes in without any problems at 
> all. Sometimes i even loose some paths after rescanning.....again, i had 
> no problems at all with CentOS 4.x.
> 
> I use the Qlogic script (Dynamic Target and LUN Discovery 
>
<http://support.qlogic.com/support/EULATemplate/Template.aspx?TemplateID=9&path=http://download.qlogic.com/ms/56614/ql-dynamic-tgt-lun-disc-2.2.tgz>
> 2.2) to scan for new luns.
As already said, the rdac driver/userspace tool contains a hot_add
script that takes care of that .. but i admit that i've not yet updated
those machines to 5.1 because of a need to rebuild the rdac kmod
...
> 
> Has anyone had any issues with scanning for new devices off san after 
> upgrading to 5.1 ?
> 
> Thanks,
> Finnur

-- 
Fabian Arrotin <fabian.arrotin at arrfab.net>
Solution ? 
echo '16i[q]sa[ln0=aln100%Pln100/snlbx]sbA0D4D465452snlbxq' | dc
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Fabian Arrotin wrote:
> On Fri, 2007-12-14 at 21:55 +0000, Finnur ?rn Gu?mundsson wrote:
>   
>> Hi,
>>
>> I got few servers (IBM HS20,HS21 blades, IBM xSeries 3650 & others)
>> connected to a dual fabric san throught Qlogic HBA's (23xx, 24xx). 
>> Multipathing is done with device-mapper-multipath.
>>     
>
> I've installed the same machines on several IBM DS3xxx or DS4xxx SANs
> but i used the provided rdac multipath driver (adviced by IBM in their
> documentation)
>
>   
>> On CentOS 4.x i can scan for new scsi devices without any problems, get
>> them up with multipathing & use them without any problems.
>>
>> However, after i started installing CentOS 5.1 (did not notice this 
>> problem with CentOS 5) i cannot seem to rescan without huge problems. 
>> Sometimes when i rescan after presenting a new LUN to the server
nothing
>> is detected, and sometimes the device comes in without any problems at 
>> all. Sometimes i even loose some paths after rescanning.....again, i
had
>> no problems at all with CentOS 4.x.
>>
>> I use the Qlogic script (Dynamic Target and LUN Discovery 
>>
<http://support.qlogic.com/support/EULATemplate/Template.aspx?TemplateID=9&path=http://download.qlogic.com/ms/56614/ql-dynamic-tgt-lun-disc-2.2.tgz>
>> 2.2) to scan for new luns.
>>     
>
> As already said, the rdac driver/userspace tool contains a hot_add
> script that takes care of that .. but i admit that i've not yet updated
> those machines to 5.1 because of a need to rebuild the rdac kmod ...
>   
>> Has anyone had any issues with scanning for new devices off san after 
>> upgrading to 5.1 ?
>>
>> Thanks,
>> Finnur
>>     
>
>
>   
> ------------------------------------------------------------------------
>
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> http://lists.centos.org/mailman/listinfo/centos
>   
Hi,

Sorry, forgot to mention i got a IBM SVC as a storage device. IBM 
recommends using device-mapper-multipath for RHEL 5. There is not SDD 
(propriatory IBM driver for the ESS, DS6000/DS8000, SVC devices) for RHEL 5.


Bgrds,
Finnur

Hi,

On 2.6 kernels, I always used to issue the commands directly:

1) Find what's the host number for the HBA:

ls /sys/class/fc_host/

(You'll have something like host1 or host2, I'll refer to them as
host$NUMBER from now on)

2) Ask the HBA to issue a LIP signal to rescan the FC bus:

echo 1 >/sys/class/fc_host/host$NUMBER/issue_lip

3) Wait around 15 seconds for the LIP command to have effect

4) Ask Linux to rescan the SCSI devices on that HBA:

echo - - - >/sys/class/scsi_host/host$NUMBER/scan

The wildcards "- - -" mean to look at every channel, every target,
every
lun.

That's it. You can look for log messages at "dmesg" to see if
it's working,
and you can look at /proc/scsi/scsi to see if the devices are there.

These commands should work with all HBAs, at least I know for sure they work
with QLogic's and Emulex'es.

Hope it helps,
Filipe
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