RE: LVM and multiple HBA ports

["Yang, Fred" <FYang@nshs.edu>]

Title: RE: LVM and multiple HBA ports

It seems the trend is OS vendor start to put the MPIO feature into OS, e.g. SUN's MPxIO, IBM's MPIO(Only on AIX5.2), and even Microsoft start program to implement MPIO in it's Windows OS. I guess that's one of the reason why relatively smaller storage vendor don't want to jump in to develop their own driver. 

I'm really curious are there anybody heard about any project about MPIO on Linux?

 

Fred

---

From: linux-lvm-bounces@redhat.com [mailto:linux-lvm-bounces@redhat.com] On Behalf Of Dan Bar Dov
Sent: Thursday, April 22, 2004 4:49 AM
To: 'LVM general discussion and development'; 'csc@cadence.com'
Subject: RE: LVM and multiple HBA ports

I wouldn't call them 'most storage vendors'  rather the 'large vendors'.

 

I'm using an Infortrend (taiwanese vendor) storage controller. They and all the other small vendors, do not support any multiple path failover drivers for Linux. Qlogic HBA has some support in their driver, but only if you user their user mode management software, which I cannot use since they support only Intel and I'm on PPC. They won't supply any documentatin etc regarding how to use it programatically.

 

People who use Linux because its not expensive, also use inexpensive storage. It does not mean they don't want to use advanced features.

 

Dan

-----Original Message-----
From: Yang, Fred [mailto:FYang@nshs.edu]
Sent: Wednesday, April 21, 2004 7:36 PM
To: 'csc@cadence.com'; 'LVM general discussion and development'
Subject: RE: LVM and multiple HBA ports

What storage you are using? Most storage vendor has their own multi path software, e.g. EMC's powerpath, IBM's SDD. We are using IBM ESS, and we just use the vpath device to create PV, the SDD actually do the load balancing&failover between multiple path.

-Fred

-----Original Message-----
From: linux-lvm-bounces@redhat.com [mailto:linux-lvm-bounces@redhat.com] On Behalf Of Chris Croswhite
Sent: Wednesday, April 21, 2004 12:17 PM
To: LVM general discussion and development
Subject: Re: LVM and multiple HBA ports

Is this a multipathed device?  I first create an MD device of a particular lun like this:
mdadm -C -f -l mp -n 1 -x 1 /dev/md0 /dev/sd<x> /dev/sd<y>

where x is channel A of the device and y is channel B.

You can then verify it by:
mdadm --detail /dev/md0

Does this help?

On Wed, 2004-04-21 at 09:04, Dan Bar Dov wrote:
> I have a problem using two (or more) ports connected to the same storage.
>
> Linux does not identify that the two LUNs it discovers is actually the same.
> When I create a PV all is well.
> The PV gets created and is ACTIVE. However, through the other port,
> the PV is also discovered, but is marked INACTIVE in the LVM database.
>
> When I try to create a VG using the active path, LVM scans all PVs in order.
> If it finds the INACTIVE instance first, the VG creation fails.
>
> I'm using LVM 1.0.3, please let mw know if such a situation
> (connecting storage through multiple ports) is handled better in
> another version, or suggest how to overcome the problem.
>
> Thanks,
> Dan
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
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> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

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