Networker

Re: [Networker] NetWorker + Windows SAN Tapes

2006-09-06 09:08:00
Subject: Re: [Networker] NetWorker + Windows SAN Tapes
From: "Greggs, Dana" <c-dgreggs AT STATE.PA DOT US>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Date: Wed, 6 Sep 2006 09:01:04 -0400
You can do it in Windows but the flag is not set "in Windows" but on the
device. I have 4 FC attached libraries on W2K3 and it works. There is a
caveat in that at times I have to resync the Library and Networker when
there are changes on the SAN but persistent binding does work.

Thanks,

Dana

-----Original Message-----
From: EMC NetWorker discussion [mailto:NETWORKER AT LISTSERV.TEMPLE DOT EDU] On
Behalf Of Davina Treiber
Sent: Wednesday, September 06, 2006 6:56 AM
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Subject: Re: NetWorker + Windows SAN Tapes

Gaddy wrote:

>Hi all,
>
>this is a little bit OffTopic, but hurts us at least twice a month ...
>
>We have some "Dedicated Storage Nodes", which share fibre attached
>LTO drives in an 3-frame IBM3584.
>Switches\Directors are McData, HBAs different types of Emulex cards.
>All tape drives (WWPNs) are bound to SCSI addresses using elxcfg / 
>HBAnywhere.
>
>If, for some reason (defect), we power off a tape drive,
>some of the Storage Nodes (esp. Windows2003)
>readdresses the devices "on the fly", e.g. \\.\Tape3 will become
\\.\Tape2
>(SCSI adresses do not change, because they are bound as described
above).
>
>Unfortunately NetWorker is not very happy with this behavior!
>( I think, many of you can imagine that, can't you? )
>
>So my questions are:
>
>a) Can I stop Windows2003 from changing the logical device addresses?
>  
>
I don't think there is a way to stop Windows doing this. Even when you 
have implemented persistent binding there is still no way to force the 
correct mapping of Windows device files to SCSI addresses. This is a 
serious design limitation in Windows. Compare this to Solaris where 
device files are only mapped when you force them to be. I'm not sure how

well Linux handles this situation, it is something I have been meaning 
to find out.

>   
>b) If I cannot, can I rearange the addresses ONLINE without
>   rebooting the server (which is typical a large SAP+Oracle in
production)
>  
>
Again I don't know of a way to do this. I would like to know if there
is.

Of course this does not just apply to SAN connected tape devices, it 
would be just as much of a problem in a pure SCSI environment. Sadly 
this is one of the reasons I would always advise clients not to use 
Windows for large NW servers or storage nodes.

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