Move to another server?

[Simon Matter]

> Hi,
>
> --On 21. Januar 2005 23:57:25 Uhr +0100 Simon Matter
> <simon.matter at ch.sauter-bc.com> wrote:
>
>>> could you please specify the exact kernel versions you are referring
>>> to?
>>> I'm not sure which version update 3 was. We are currently running
>>> 2.4.21-15.0.3.ELsmp. We can't really use a newer version, because we
>>> need
>>> IBM's sdd driver for SAN vpaths and they are slow in certifying new
>>> kernels
>>> ... maybe telling them about specific issues might speed up the
>>> process.
>>
>> A lttle bit OT: I don't know the IBM thing but I expect it's all about
>> multipathing some FC connected SAN disks. Maybe you also use qla2300
>> cards. We were forced to use HP's secure path for this. It's expensive
>> and
>> it's also never available for updated kernels in time. Now we are just
>> using the multipathing/failover which is built in into the qla2300
>> drivers
>> of the newest RedHat kernels and it works like a charm.
>
> thanks for the info. I've told our systems people about this and they are
> now playing around with it. Our situation is probably a little more
> complicated than usual because of an additional layer of virtualization
> that is introduced by the IBM SVC stuff. There are four "raw" devices
> visible for each volume ...

In our case it's HP EVA3000 which seems to do exactly the same. For a
virtual disk on the EVA, you get four raw scsi devices, but you can only
talk to two of them. I don't remember exactly but I made alot of tests
with the following configurations:
- HP Secure Path software -> Qlogic driver without failover
- Linux multipath using MD -> Qlogic driver without failover
- Qlogic driver with builtin failover

All three methods worked well. The advantage of HP's Secure Path software
should have been that it also provides load balancing over the two
independant FC paths. Only through tests and some notes in the release
notes I learned that HP just plans to support this feature in a future
release...

Simon


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