Two Linux nodes are presented the same storage; but the LUNs are discovered/named differently.

[unix syzadmin]

Hi Matt,

Thanks.
I am an UNIX admin; not a DBA.
>From what I know; DBA plan to use ASM to manage the storage.

However; my question is still valid.
If two nodes are presented the same storage; why would a EMC LUN  on node1
be discovered and named differently on node2?

node1:

emcpowera --> lun# 1346

# ls -ld /dev/emcpowera
brw-r----- 1 root disk 120, 0 Sep 16 16:17 /dev/emcpowera


node2:
emcpowerg --> lun#1346

# ls -ld /dev/emcpowerg
brw-r----- 1 root disk 120, 96 Sep 16 16:23 /dev/emcpowerg


>From the above "emcpowera" on node1 is called "emcpowerg" on node2.
The LUN number shown in powerpath is same for both of them.
Also the minor and major device numbers for the LUNs are different on both
the nodes.

It would be better if LUN# 1346 would be discovered as" ecmpowera" on both
the nodes with the same minor/major numbers.
I know that most of these are going to be used by ASM and I don't have to
worry.

But if there was a problem with LUN#1346; i would have to deal with the two
different device names in both the nodes.
This is going to be in production soon and down the line there might be more
storage that might get added.  So for troubleshooting and maintenance I
think it would help if these LUNs were named/discovered similarly on both
the nodes.

Thanks,



On Mon, Sep 19, 2011 at 9:54 AM, Matty Sarro <msarro at gmail.com> wrote:

> You can configure the names used if you want, but you may want to
> consider using oracle ASM - then it won't matter what the disks are
> named, only what the ASM volume is called. This would only be done on
> the first server, and the ASM data should be read by the second server
> automatically.
> -Matt
>
> On Mon, Sep 19, 2011 at 9:48 AM, unix syzadmin <unixsyzadmin at gmail.com>
> wrote:
> > Hi,
> >
> > We are setting up 2 RHEL 5.6 server to be used in the oracle RAC cluster
> > environment.
> >
> > We have about 25 X 200G EMC LUNs presented to the servers.
> > Since it is the RAC cluster; same LUNs are presented to both the nodes.
> >
> > However I see that the names for the LUNs are different on both the
> servers.
> > for example: "emcpowera"  on node1 is discovered as" emcpowerg" in node2.
> >
> >
> > Any suggestions/ideas?
> > Thanks,
> > --
> > redhat-list mailing list
> > unsubscribe mailto:redhat-list-request at redhat.com?subject=unsubscribe
> > https://www.redhat.com/mailman/listinfo/redhat-list
> >
>
> --
> redhat-list mailing list
> unsubscribe mailto:redhat-list-request at redhat.com?subject=unsubscribe
> https://www.redhat.com/mailman/listinfo/redhat-list