I would need a lot more specifics to be exact, but let's
Hello again,
I would need a lot more specifics to be exact, but let's try to address this
with what we have,
You mention an i/o blade, so your library is Dual attached, and can manage a
failover process if it detects that one of it's directly attached links goes
down. And from the Server perspective MPIO should do the same.
You mention that your server see's the libraries+drives with different id's
when the library forces a failover. This indicates that both library
connections are available to at least one connection on the server. And, that
the Server is not allowing an identical device id on an alternate path.
So far everything is working as designed, remember - regardless of whether a
link on the Server or the library is dropped, the Server will see the active
device id's change.
The real test would be to unplug the fiber from alternate HBA's on the server
to verify that all HBA's on the Server can at least "see" both of the library
connections. If not then there are more basic things to take care of first.
Now you also stated that you had to re-configure Networker in order for it to
see the newly active devices after the library forced a failover.. This
indicates that Networker is not currently configured to use the Windows MPIO. I
would go old school, delete the library and tape drives, recheck the MPIO
config and re-install if you aren't sure, reboot the server, start Networker,
and run the "scan for devices".
What I have seen this do in the past ( utilizing EMC Powerpath for MPIO ), is
that a third set of device id's is now available. These new id's are the
"virtual" devices you will want to use in your Networker configuration. Any
version prior to 7.4 would have a fit with this though.
________________________________
From: Manel Rodero <manel AT FIB.UPC DOT EDU>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Sent: Thu, November 5, 2009 6:51:15 AM
Subject: Re: [Networker] Multipath to our new Scalar i500 Library
Hi,
Yes. I've read about the multipath. I've installed the MPIO feature in Windows
Server 2008 but I don't know how to continue.
For example, I don't know if I must get a DSM (device specific module) and, if
yes, from who? Quantum? I've searched a lot, and I didn't found anything
related to DSM for the Scalar i500.
Other thing is how to specify "mpio-ed devices" in the MPIO management tool (it
must ve vendor + device but I don't know how to obtain this number/string).
So, at this moment I'm lost. If we don't use this multipath technique we will
see all drives/library duplicated in our OS, then in Legato.
We've tried to change some config in the Scalar for supporting "failover".
Then, we can see only 1 time each drive and library, but after a problem with
the path, the library does the failover and when the OS sees the drive/library,
they have different names (i.e. Tape0 -> Tape3) and we must to reconfigure
Legato.
So, the question is that is possible to use this library with their feature of
having 2 different paths for the drives (using the I/O Blade) but being
transparent to Legato. Can we define some device in the OS and use this name in
Legato? Which Legato version is multipath, failover, etc. aware? We will try to
use 7.4.4 as in our old server.
I hope someone with more experience in SAN/FC can give some ideas about how to
follow.
Thank you very much.
Rudy Munguia wrote:
> Hello,
>
> You will want to install your multipathing agents. This will keep track of
> the active path ( some will even allow the two paths to be used
> simultaneously ) and only present a single device instance to the OS, you can
> then point Networker at this device instance, and it should only see 1
> instance of each drive.
>
> Your mileage may vary based on the revision of networker you have
> implemented, older revisions will want to use their own device drivers to
> address the drives directly which will interfere with the multipathing agents.
>
> Rudolfo
>
>
>
>
> ________________________________
> From: Manel Rodero <manel AT FIB.UPC DOT EDU>
> To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
> Sent: Mon, October 26, 2009 4:04:49 AM
> Subject: [Networker] Multipath to our new Scalar i500 Library
>
> Hello,
>
> We've recently purchased an Scalar i500 library from Quantum (including the
> I/O Blade module too).
>
> Our library has 2 LTO-4 FC drives connected to our backup server through the
> I/O blade. Our backup server has 2 x HBA QLE2460 (1 port each one) so we can
> connect the 2 host output of the I/O blade to the 2 ports on the server.
>
> But, as expected, under Windows (we're using Windows Server 2008) we see 4
> drives (instead of 2) and 2 libraries (instead of 1) as them are presented by
> two paths.
>
> As I'm very new to all the SAN concepts, zones, failover, etc. I would like
> to ask for some tips about how to set this environment for having dynamic
> multipath for every drive and the library.
>
> If I change some settings in the library I finally got it presenting to the
> host only 2 drives + 1 library (something related to poin-to-point and
> failover ports). But, if I configure Legato using these settings, when we
> disconnect one FC and the library presents the drives using another path,
> Legato see the drives with another name (i.e. initially \\.\Tape0 and
> \\.\Tape1 and after the change as \\.\Tape2 and \\.\Tape3).
>
> So I suppose I need to use aliases, isn't it? Or must I install multipath
> software in Windows Server 2008? I've installed the optional feature but I
> don't know how to continue with this setup.
>
> If someone can give me some tips/info about what to read or look for, I'll be
> very grateful.
>
> Thank you very much!
>
--
Manel Rodero Blánquez
o o o IT Systems Manager
o o o Laboratori de Càlcul
o o o Facultat d'Informàtica de Barcelona
U P C Universitat Politècnica de Catalunya - Barcelona Tech
E-mail : manel AT fib.upc DOT edu
Tel. : +34 93 401 0847
Web : http://www.fib.upc.edu/
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