Hi,

Are there any multipath (load-balancing and fail over) tools for
RedHat? I would like to use Hitachi storage via Fibre Channel using 2+
paths. Therefore, I need a software for multipath. I do not want to use
HDS' HDLM (Hitachi Dynamic Link Manager) because of its supporting
issues.

Thanks and best regards,
Mehmet

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<mhmtzdmr@gmail.com> wrote in message
news:1135188659.115425.140470@o13g2000cwo.googlegroups.com...
> Hi,
>
> Are there any multipath (load-balancing and fail over) tools for
> RedHat? I would like to use Hitachi storage via Fibre Channel using 2+
> paths. Therefore, I need a software for multipath. I do not want to use
> HDS' HDLM (Hitachi Dynamic Link Manager) because of its supporting
> issues.
>
> Thanks and best regards,
> Mehmet

What supporting issues are you encountering?? Don't know about the Linux
version, but on Solaris and Windows, HDLM works quite well.

Rob

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On Wed, 21 Dec 2005 22:37:50 +0100, "Rob Turk" wrote:

><mhmtzdmr@gmail.com> wrote in message
>news:1135188659.115425.140470@o13g2000cwo.googlegroups.com... 
>
>What supporting issues are you encountering?? Don't know about the Linux
>version, but on Solaris and Windows, HDLM works quite well.

As Rob says, HDLM is pretty good and if you have HDS storage you are
recommended to use it.  What issues are you having?

If you just want an alternative (but not always as good) you could try
Veritas DMP, or if you use Qlogic HBAs they ship with multi-path
software in the SANsurfer suite.

However, it would be very rare to fit your storage environment around
your choice of multi-pathing software.

HVB

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I mean for example HDLM is not supported for RHEL 4* yet and nobody
knows when HDS will support it. Does SANsurfer suite perform
load-balancing and path failover?

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<mhmtzdmr@gmail.com> wrote in message
news:1135206081.474293.282160@o13g2000cwo.googlegroups.com...
>I mean for example HDLM is not supported for RHEL 4* yet and nobody
> knows when HDS will support it.

HDS is always reluctant to call a certain combination "supported". It means
that they have actually tested in in their labs in many configurations, both
good and bad, so they understand all the ins and outs of the configuration.
When they stick RHEL4 on the "supported" list then they can actually help
you when something isn't working for you. This takes time.

For you this means it comes down to a business choise. If you run HDS
storage with a need for path failover then you have a business critical
application running. Does that application demand RHEL4? Maybe you are
better of selecting RHEL3 instead, which is well understood, stable and
supported. What does RHEL4 offer you that isn't in RHEL3 and that your app
absolutely  must have?!?

If you app is not business critical and you can live with an 'unsupported'
config then go ahead and install HDLM on your RHEL4 system. Chances are it
will work just fine. Just don't call HDS if it doesn't..

Rob

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On 21 Dec 2005 15:01:21 -0800, mhmtzdmr@gmail.*** wrote:

>I mean for example HDLM is not supported for RHEL 4* yet and nobody
>knows when HDS will support it. Does SANsurfer suite perform
>load-balancing and path failover?

Is that it???  ;)  Speak to your SE at HDS.  If it's important to you,
HDS will add your config to the 'to be qualified' testing list.  If
you ask really nicely you might be able to get this done quite
quickly.

As Rob Turk suggested, if you're in a big hurry, go with RHEL3 or give
RHEL4 a try - it'll probably work anyway.

Qlogic aren't good at making this obvious, but yes, SANsurfer *does*
include load-balancing (basic) and path-failover and it comes *FREE*
with every Qlogic HBA.

HVB.

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mhmtzdmr@gmail.com wrote:
> Are there any multipath (load-balancing and fail over) tools for
> RedHat? I would like to use Hitachi storage via Fibre Channel using 2+
> paths. Therefore, I need a software for multipath. I do not want to use
> HDS' HDLM (Hitachi Dynamic Link Manager) because of its supporting
> issues.

You've got a few options that I'm aware of although we don't use HDS
storage so you'll have to double-check the compatibility matrices.

1.  Veritas DMP.  The Storage Foundation Suite license for Linux lists
at about $1K.  You'll get VxFS and DMP (HDS is supported according to
http://ftp.support.veritas.com/pub/...aroqui.free.fr/
dm-multipath is the Red Hat approach going forward.  It's in RHEL 4
today (starting with the latest update I think) and supports a large
number of storage arrays.  There's a mailing list at
https://www.redhat.com/mailman/listinfo/dm-devel

I've been lurking on the mailing list for a few months even though I'm
not a developer and it's interesting who's doing the development work
here.  It's not just Red Hat - it's them plus SuSe, IBM, EMC, NetApp,
Cisco, HP, and more.  It seems like both customers and vendors hate the
PowerPath, SecurePath, etc. proprietary solutions and the open source
dm-multipath is going to make them all go away.  It reduces the cost of
SAN-connectivity by a bunch since in some cases the multipathing
software is more than the cost of the server itself.

../Ed

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