The zoning process simply associates a server HBA port on the server
with the HBA port on the disk device.
Persistent binding is a function of the OS and HBA drivers on the
server. Within the server configuration, the HBA must be told that a
device with a particular ID (i.e. /dev/rmt1) is always to be associated
with a physical device with a specific ID (i.e. WWPN). This is
typically performed by a configuration file that manages the HBA
configuration.
On Solaris with an Emulex HBA, the file /kernel/drv/lpfc.conf will allow
you to manage persistent bindings by associating a specific WWPN or WWNN
to a specific scsi ID:
e.g. fcp-bind-WWPN="500a098386f7d4f3:lpfc0t0";
You also need to ensure that automatic reconfiguration is NOT set.
Automatic reconfiguration can be particularly vexing in a fiber channel
loop environment where device contention may cause indeterminent delays
with multiple target devices (tape drives) attached to a single
initiator (server HBA).
Cheers,
Neil Strand
Storage Engineer - Legg Mason
Baltimore, MD.
(410) 580-7491
Whatever you can do or believe you can, begin it.
Boldness has genius, power and magic.
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Hart, Charles A
Sent: Monday, October 18, 2010 4:58 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] Looking for SAN/tape experts assistance
This may be a dumb response but this behavior is similar in Windows and
or Solaris, I thought if the person that zoned the device enabled
persistent binding these devices would not re-order on but as it scans
the FC.
Did I completely miss it?
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
giblackwood
Sent: Monday, October 18, 2010 1:26 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: [ADSM-L] Looking for SAN/tape experts assistance
Mr Forray,
I know a lot about this problem you are dealing with. My name is George
Blackwood. I was a Systems Engineer with IBM for 30 years. Among other
things, I was a SAN, tape, and TSM specialist. I have been retired for
2 years, 1 month. I have my own consulting business doing what I did
when I was an IBMer.
When Linux is rebooted (RedHat, SLES, whatever), it will scan and
re-discover its SCSI and FCP (Fibre Channel Protocol) tape resources
without regard of what it knew about those same devices before the
reboot (this is not the case with some UNIX systems).
So, unless you have one changer and one tape drive, you have no
guarantee that the Linux device numbers will be the same after reboot.
So, chances are IBMtape0 will be IBMtape20 the next time you reboot.
IBM's answer is to set "SANDISCOVERY ON". This works sometimes for a
small number of drives (under 20), and will sometimes work for more.
But after 18 months of being in and out of IBM PMRs and "CritSits", I
have given up on sandiscovery to fix this issue.
I wrote a BASH script to fix this issue. A current customer of mine has
8 RedHat Linux servers sharing 12 TSM instances (we can move them around
as need be). Two instances are Library Managers. All instances have
access to 4 EMC EDLs. Each EDL has 80 drives. So that comes to 3890
drives paths, plus 4 Library paths to maintain.
The script I wrote discovers what TSM instances (Library Servers and
Clients) are running on a given Linux server that has just been
rebooted. It compensates for any drives that may be mounted, or any
Libraries that are in use, and re-defines all the Library and drive
paths for any TSM instance on a given Linux server.
So if one of the 8 servers needs to be rebooted, the script is run on
that server after reboot. There is no need to unmount and quiesce
Libraries. The only requirement is the Library Managers must be up.
The script will also find what drives are in a SCSI reserve "lock out".
And, it is safe to be run during full production time.
I can give you a few pointers to write a similar script (for free), or
for a fee, write it for you. I guarantee my work.
George Blackwood
Blackwood Data Protection Consulting, LLC
785-218-9961
georgeblackwood AT sunflower DOT com
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