HELP 6850 running RHEL 3.0 update 6 on EMC CX700

Matias Oberti matias.oberti at gmail.com
Mon Apr 10 16:14:34 CDT 2006


Hi Thomas,
  For what I understand your first problem comes from the qla2300 module
loading before the mraid (?) module. If this is actually your problem, the
kernel is seeing the clariion LUNs and assigning them device nodes (sda,
sdb, etc.) and after that, it sees the mraid (or whatever scsi raid card
you're using) module and assigns that LUN the sdeo device node. That can be
corrected in /etc/modules.conf, where you'll have to check and correct the
order in which modules are loaded and create a new initrd image refelcting
those changes.

  Second issue: always use the pseudo name (emcpowera, emcpowerb, etc.).
Apparently you have four front-end ports connected to your server, which
means you're having two live paths and two 'backup' paths as one LUN is
owned by only one SP at a time. The pseudo names are the PowerPath way to
provide the OS the virtualization layer that will do the failover and
load-balancing work. In case you use one of the real names and you're lucky
enough to be using an active path (50% chance) it will work, but in case
that path gets cut off by any reason PowerPath won't be able to provide
failover services, because you're not using its device, you'd be actually
skipping it. Also you'd be missing the benefit of load-balancing between the
two active paths to your LUNs.

Hope I helped.

Best Regards.

Matias Oberti.


On 4/8/06, Thomas Northup <thomaslnorthup at yahoo.com> wrote:
>
>  When the LUNS are presented to the host it changes the local drive to
> something like sdeo.
> How can I keep it from doing that?
>
> Plus on the SAN should I use the Pseudo name to build the file systems or
> the real name.
> See example below.
>
>
> [root at hmmdb root]# powermt display dev=all | more
> Pseudo name=emcpowerk
> CLARiiON ID=APM0003124 [HCC_DB]
> Logical device ID=6006016011511500085DA11 [LUN 75]
> state=alive; policy=CLAROpt; priority=0; queued-IOs=0
> Owner: default=SP B, current=SP A
>
> ==============================================================================
> ---------------- Host ---------------   - Stor -   -- I/O Path -  -- Stats
> ---
> ### HW Path                 I/O Paths    Interf.   Mode    State  Q-IOs
> Errors
>
> ==============================================================================
>   3 QLogic Fibre Channel 2300 sdai       SP B0     active  alive      0
> 0
>   2 QLogic Fibre Channel 2300 sde        SP A0     active  alive      0
> 0
>   2 QLogic Fibre Channel 2300 sdo        SP B1     active  alive      0
> 0
>   3 QLogic Fibre Channel 2300 sdy        SP A1     active  alive      0
> 0
>
>
>
>
> Thomas Northup
>
> thomaslnorthup at yahoo.com
>
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