Re: [CentOS] Qlogic HBA scanning issues with CentOS 5.1 ?

[Fabian Arrotin]

On Fri, 2007-12-14 at 21:55 +, Finnur Örn Guðmundsson 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 
> 
>  
> 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 <[EMAIL PROTECTED]>
Solution ? 
echo '16i[q]sa[ln0=aln100%Pln100/snlbx]sbA0D4D465452snlbxq' | dc


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Re: [CentOS] Qlogic HBA scanning issues with CentOS 5.1 ?

[Finnur Örn Guðmundsson]

Fabian Arrotin wrote:

On Fri, 2007-12-14 at 21:55 +, Finnur Örn Guðmundsson 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 
 
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




  



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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
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Re: [CentOS] Qlogic HBA scanning issues with CentOS 5.1 ?

[Filipe Brandenburger]

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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Re: [CentOS] Qlogic HBA scanning issues with CentOS 5.1 ?

[Filipe Brandenburger]

On Dec 17, 2007 9:34 AM, Filipe Brandenburger <[EMAIL PROTECTED]> wrote:

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

This was actually introduced in CentOS 4.3 (and upstream RHEL4.3):
http://www.centos.org/docs/4/html/release-notes/as-x86/RELEASE-NOTES-U3-en.html#id3641770

Filipe
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