[Linux-cluster] Duplicate Volumes, GFS fail over

[Greg Swift]

isplist at logicore.net wrote:
> Thanks.
>
> I'll look into this. 
>
> Does this have to be installed on every server in the cluster? Contacting the 
> vendor won't do me any good since I don't have support for 90% of the hardware 
> being used :). Has to be something I can do on my own with what I've got.
>
> Mike
>   
every box that has multiple paths would need to have it to behave 
properly.  Like i said before, it might not be that difficult. 

You can use the default /etc/multipath.conf by just commenting out the 
blacklist section.  My default /etc/multipath.conf looks like this:

devnode_blacklist
{
       ##this block the primary local hard disk, change to meet your setup
       devnode "^sda"
       ##this ignores lots of stuph that is not relevant at all in most 
circumstances
        devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
       ##this blocks ide based devices
        devnode "^hd[a-z][0-9]*"
       ##i dont remember what this blocks.
        devnode "^cciss!c[0-9]d[0-9]*[p[0-9]*]"
}
defaults {
        ## use user friendly names, instead of using WWIDs as names.
        user_friendly_names yes
}

I define a devices section for the emc box i work with that looks like this:
devices {
        ## Device attributes requirements for EMC Symmetrix
        ## are part of the default definitions and do not require separate
        ## definition.
        ## Device attributes for EMC CLARiiON
        device {
                vendor "DGC "
                product "*"
                path_grouping_policy group_by_prio
                getuid_callout "/sbin/scsi_id -g -u -s /block/%n"
                prio_callout "/sbin/mpath_prio_emc /dev/%n"
                path_checker emc_clariion
                path_selector "round-robin 0"
                features "1 queue_if_no_path"
                no_path_retry 300
                hardware_handler "1 emc"
                failback immediate
        }
}

but thats not necessary.  it should look at what you have and use 
defaults based on pre-configured assumptions (correct me if i'm wrong ppl).

-greg

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