[linux-lvm] LVM in Dual Path SAN Environment

[linux-lvm] LVM in Dual Path SAN Environment

[Andreas G. Schindler]

A Question to the LVM Guy(s):

We would like to use Linux LVM to overcome the fact, Linux doesn't 
currently support Dual-Path access to SAN (Fibre-Channel) units.

Rumors are, LVM is able to detect multiple paths to a PV (in my case
a SAN SCSI LUN) and will rearrange it to one single PV.

As far as i see, this should solve the problem during regular operation
(i.e. both paths to the SAN active). But what about the really interesting
case of failure on one link? If this is the currently 'active' link (that
one, still in t LVM's PV list), we need a failover and rearrangement
of the PV list on the fly.

Does this work ??

Many thanks in advance

Regards, Andreas

-- 

Dr. Andreas G. Schindler        c/o Alpha Zero One Computersysteme GmbH
schindler@az1.de                Frankfurter Str. 141, D-63303 Dreieich
Tel +49 6103 57187 21           Germany

Re: [linux-lvm] LVM in Dual Path SAN Environment

[Heinz J . Mauelshagen]

On Wed, Sep 11, 2002 at 11:39:32AM +0200, Andreas G. Schindler wrote:
> A Question to the LVM Guy(s):
> 
> We would like to use Linux LVM to overcome the fact, Linux doesn't 
> currently support Dual-Path access to SAN (Fibre-Channel) units.
> 
> Rumors are, LVM is able to detect multiple paths to a PV (in my case
> a SAN SCSI LUN) and will rearrange it to one single PV.

Correct.

> 
> As far as i see, this should solve the problem during regular operation
> (i.e. both paths to the SAN active). But what about the really interesting
> case of failure on one link? If this is the currently 'active' link (that
> one, still in t LVM's PV list), we need a failover and rearrangement
> of the PV list on the fly.
> 
> Does this work ??

Not so far. We want to have multipathing with failover support
in LVM2 this year.

> 
> Many thanks in advance
> 
> Regards, Andreas
> 
> -- 
> 
> Dr. Andreas G. Schindler        c/o Alpha Zero One Computersysteme GmbH
> schindler@az1.de                Frankfurter Str. 141, D-63303 Dreieich
> Tel +49 6103 57187 21           Germany
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html

-- 

Regards,
Heinz    -- The LVM Guy --

*** Software bugs are stupid.
    Nevertheless it needs not so stupid people to solve them ***

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Am Sonnenhang 11
                                                  56242 Marienrachdorf
                                                  Germany
Mauelshagen@Sistina.com                           +49 2626 141200
                                                       FAX 924446
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Re: [linux-lvm] LVM in Dual Path SAN Environment

[Ragnar Kjørstad]

On Wed, Sep 11, 2002 at 11:39:32AM +0200, Andreas G. Schindler wrote:
> A Question to the LVM Guy(s):
> 
> We would like to use Linux LVM to overcome the fact, Linux doesn't 
> currently support Dual-Path access to SAN (Fibre-Channel) units.

If you use md this should work just fine. There has been a number of
patches lately that hasn't been included in the main kernel yet, so you
may want to patch a little. 


-- 
Ragnar Kjørstad