Hi Gaddy

You make a great point!

http://download.qlogic.com/drivers/5419/QLogic_Solaris.pdf describes Qlogic's 
persistent binding implementation.  The persistence implemented by the FC HBA 
driver provides the binding of the Fibre Channel entity (pairing the WWNN/WWPN 
of the storage and the host HBA number) to a SCSI logical unit number (LUN).  
That's it; it doesn't deal with the logical device naming at all.

ftp://ftp.software.ibm.com/storage/devdrvr/Doc/IBM_Tape_Driver_IUG.pdf 
describes (among other things) the IBM tape driver's support for persistent 
naming on AIX, HP-UX and Solaris (note that Windows is not in that list). 
However, in the README file for the latest IBM tape driver for Windows 
(ftp://ftp.software.ibm.com/storage/devdrvr/Windows/Win2003/Latest/IBMTape.W200x.Readme.txt),
 the following appears:

"Version 6.1.6.2 and later versions of the device driver have an option for 
enforcing file names for tape drives that will persist across reboots of the 
operating system.  For example, if your tape drive has the name \\.\tape3 and 
the persistent naming option is used, then \\.\tape3 will be reserved for use 
by that device after an operating system reboot.  To take advantage of this 
feature, place a DWORD value in the registry called PersistentNaming and assign 
it a value 1 at:

   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\ibmtp2k3

   and reboot your system."

So, the IBM tape driver DOES provide the LUN-to-logical device mapping that 
Pierpa seeks.

I'm sure there are other methods of providing logical device-level persistent 
mapping.  On Linux systems with the 2.6 kernel, udev provides persistent naming 
(among other things); see http://www.reactivated.net/writing_udev_rules.html 
for a primer.

If you know of other ways to provide logical device-level persistent mapping, 
please share them with this list.

Thanks
tl

Terry Lemons
Backup Platforms Group
EMC² 
where information lives
4400 Computer Drive, MS D239
Westboro MA 01580
Phone: 508 898 7312
Email: Lemons_Terry AT emc DOT com


-----Original Message-----
From: EMC NetWorker discussion [mailto:NETWORKER AT LISTSERV.TEMPLE DOT EDU] On 
Behalf Of Gaddy
Sent: Thursday, September 06, 2007 11:22 AM
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Subject: Re: [Networker] Windows2003 R2 change tape order at boot

AFAIK persistent binding on the FC-HBA affects only the physical addresses 
of the devices, scsidev AT bus.target DOT lun.
So you can easily put that addressing scheme into a fixed sequence.

Unfortunately NetWorker does not use physical addresses on Windows*,
but logical addresses like \\.\TapeX.

Logical to physical address resolution will be done on "1st come, 1st 
serve", which should be no problem, as long as all "persistent bound" 
devices are online. But, if for some reason (powered off, 
disconnected, ...) one physical address could not be resolved, the logical 
address is given to the next physical device.

This is the way MS works (from my POV).

MS knowledgebase article --> http://support.microsoft.com/kb/873337/en-us
( Thanks Michael ) could (I've never tested this, and in fact have not 
even known about before reading Michaels comment) changes this behaviour 
and adds probably some "logical persistent binding" to Windows2003.

I'd like to know, if someone has played a bit with that fix successfully.

Gaddy

To sign off this list, send email to listserv AT listserv.temple DOT edu and 
type "signoff networker" in the body of the email. Please write to 
networker-request AT listserv.temple DOT edu if you have any problems with this 
list. You can access the archives at 
http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

To sign off this list, send email to listserv AT listserv.temple DOT edu and 
type "signoff networker" in the body of the email. Please write to 
networker-request AT listserv.temple DOT edu if you have any problems with this 
list. You can access the archives at 
http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER