AW: AW: [linux-lvm] SAN setup with host mirrored disks

[Fiederling, Daniel]

Currently I have only one path to each disk but further on I'd like to test a setup with multiple paths. But am I right that I have to use md on top of multipathd for getting the two disks mirrored?
I tested different qla2xxx drivers (SuSE shipped, origanal download packages from qlogic, packages from hp) and the non suse offered much more module parameters - one of them was about en-/disabling failover. I would guess that the qla2xxx driver or the card firmware can handle multiple paths. But I'm not sure about that...


-----Ursprüngliche Nachricht-----
Von: linux-lvm-bounces at redhat.com [mailto:linux-lvm-bounces at redhat.com] Im Auftrag von Kelly Sauke
Gesendet: Montag, 17. Juli 2006 15:36
An: LVM general discussion and development
Betreff: Re: AW: [linux-lvm] SAN setup with host mirrored disks

> Why do I have to expect io errors when using md? What is special about the Clariion setup? I would expect that the san disks are only "normal" scsi disks for linux...
>   
The difference comes in how the multiple paths to the same disk are 
handled under linux.  If you only have one path to each disk, then this 
doesn't apply to you. I guess I forgot to clarify if you had more than 
one path.   Anyway, if you have multiple paths mpio knows which is the 
Active path and which is the Passive path.  Sending IO down a passive 
path will result in IO errors.